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Search found 171 results on 7 pages for 'sysctl'.

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• Why is domU faster than dom0 on IO?

  - by Paco

  I have installed debian 7 on a physical machine. This is the configuration of the machine: 3 hard drives using RAID 5 Strip element size: 1M Read policy: Adaptive read ahead Write policy: Write Through /boot 200 MB ext2 / 15 GB ext3 SWAP 10GB LVM rest (~500GB) emphasized text I installed postgresql, created a big database (over 1GB). I have an SQL request that takes a lot of time to run (a SELECT statement, so it only reads data from the database). This request takes approximately 5.5 seconds to run. Then, I installed XEN, created a domU, with another debian distro. On this OS, I also installed postgresql, with the same database. The same SQL request takes only 2.5 seconds to run. I checked the kernel on both dom0 and domU. uname-a returns "Linux debian 3.2.0-4-amd64 #1 SMP Debian 3.2.41-2+deb7u2 x86_64 GNU/Linux" on both systems. I checked the kernel parameters, which are approximately the same. For those that are relevant, I changed their values to make them match on both systems using sysctl. I saw no changes (the requests still take the same amount of time). After this, I checked the file systems. I used ext3 on domU. Still no changes. I installed hdparm, and ran hdparm -Tt on both systems, on all my partitions on both systems, and I get similar results. Now, I am stuck, I don't know what is different, and what could be the cause of such a big difference. Additional Info: Debian runs on a Dell server PowerEdge 2950 postgresql: 9.1.9 (both dom0 and domU) xen-linux-system: 3.2.0 xen-hypervisor: 4.1 Thanks EDIT: As Krzysztof Ksiezyk suggested, it might be due to some file caching system. I ran the dd command to test both the read and write speed. Here is domU: root@test1:~# dd if=/dev/zero of=/root/dd count=5MB bs=1MB ^C2020+0 records in 2020+0 records out 2020000000 bytes (2.0 GB) copied, 18.8289 s, 107 MB/s root@test1:~# dd if=/root/dd of=/dev/null count=5MB bs=1MB 2020+0 records in 2020+0 records out 2020000000 bytes (2.0 GB) copied, 15.0549 s, 134 MB/s And here is dom0: root@debian:~# dd if=/dev/zero of=/root/dd count=5MB bs=1MB ^C1693+0 records in 1693+0 records out 1693000000 bytes (1.7 GB) copied, 8.87281 s, 191 MB/s root@debian:~# dd if=/root/dd of=/dev/null count=5MB bs=1MB 1693+0 records in 1693+0 records out 1693000000 bytes (1.7 GB) copied, 0.501509 s, 3.4 GB/s What can be the cause of this caching system? And how can we "fix" it? Can we apply it to dom0? EDIT 2: I switched my virtual disk type. To do so I followed this article. I did a dd if=/dev/vg0/test1-disk of=/mnt/test1-disk.img bs=16M Then in /etc/xen/test1.cfg, I changed the disk parameter to use file: instead of phy: it should have removed the file caching, but I still get the same numbers (domU being much faster for Postgres)

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• Ubuntu 11.10 firewall/gateway - no client internet access

  - by Siriss

  I have read many other posts but cannot figure this out. eth0 is my external connected to a Comcast modem. The server has internet access with no issues. eth1 is internal and running DHCP for the clients. I have DHCP working just fine, all my clients can get an IP and ping the server but they cannot access the internet. I am using ISC-DHCP-SERVER and have set /etc/default/isc-dhcp-server to INTERFACE="eht1" Here is my dhcpd.conf file located in /etc/dhcp/dhcpd.conf ddns-update-style interim; ignore client-updates; subnet 10.0.10.0 netmask 255.255.255.0 { range 10.0.10.10 10.0.10.200; option routers 10.0.10.2; option subnet-mask 255.255.255.0; option domain-name-servers 208.67.222.222, 208.67.220.220; #OpenDNS # option domain-name "example.com"; default-lease-time 21600; max-lease-time 43200; authoritative; } I have made the *net.ipv4.ip_forward=1* change in /etc/sysctl.conf here is my interfaces file: auto lo iface lo inet loopback auto eth0 iface eth0 inet dhcp iface eth1 inet static address 10.0.10.2 netmask 255.255.255.0 network 10.0.10.0 auto eth1 And finally- here is my iptables.conf file: # Firewall configuration written by system-config-firewall # Manual customization of this file is not recommended. *nat :PREROUTING ACCEPT [0:0] :OUTPUT ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] -A POSTROUTING -s 10.0.10.0/24 -o eth0 -j MASQUERADE #-A PREROUTING -i eth0 -p tcp --dport 59668 -j DNAT --to-destination 10.0.10.2:59668 COMMIT *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT -A INPUT -p icmp -j ACCEPT -A INPUT -i lo -j ACCEPT -A INPUT -i eth1 -j ACCEPT -A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT -A INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT -A INPUT -m state --state NEW -m tcp -p tcp --dport 443 -j ACCEPT -A INPUT -m state --state NEW -m tcp -p tcp --dport 53 -j ACCEPT -A INPUT -m state --state NEW -m udp -p udp --dport 53 -j ACCEPT -A FORWARD -s 10.0.10.0/24 -o eth0 -j ACCEPT -A FORWARD -d 10.0.10.0/24 -m state --state ESTABLISHED,RELATED -i eth0 -j ACCEPT -A FORWARD -p icmp -j ACCEPT -A FORWARD -i lo -j ACCEPT -A FORWARD -i eth1 -j ACCEPT #-A FORWARD -i eth0 -m state --state NEW -m tcp -p tcp -d 10.0.10.2 --dport 59668 -j ACCEPT -A INPUT -j REJECT --reject-with icmp-host-prohibited -A FORWARD -j REJECT --reject-with icmp-host-prohibited COMMIT I am completely stuck. I cannot figure out why the clients cannot access the internet. Am I missing a service? Is a service not running? Any help would be greatly appreciated. I tried to be as thorough as possible but please let me know if I have missed something. Thank you!

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• What else can I do to secure my Linux server?

  - by eric01

  I want to put a web application on my Linux server: I will first explain to you what the web app will do and then I will tell you what I did so far to secure my brand new Linux system. The app will be a classified ads website (like gumtree.co.uk) where users can sell their items, upload images, send to and receive emails from the admin. It will use SSL for some pages. I will need SSH. So far, what I did to secure my stock Ubuntu (latest version) is the following: NOTE: I probably did some things that will prevent the application from doing all its tasks, so please let me know of that. My machine's sole purpose will be hosting the website. (I put numbers as bullet points so you can refer to them more easily) 1) Firewall I installed Uncomplicated Firewall. Deny IN & OUT by default Rules: Allow IN & OUT: HTTP, IMAP, POP3, SMTP, SSH, UDP port 53 (DNS), UDP port 123 (SNTP), SSL, port 443 (the ones I didn't allow were FTP, NFS, Samba, VNC, CUPS) When I install MySQL & Apache, I will open up Port 3306 IN & OUT. 2) Secure the partition in /etc/fstab, I added the following line at the end: tmpfs /dev/shm tmpfs defaults,rw 0 0 Then in console: mount -o remount /dev/shm 3) Secure the kernel In the file /etc/sysctl.conf, there are a few different filters to uncomment. I didn't know which one was relevant to web app hosting. Which one should I activate? They are the following: A) Turn on Source Address Verification in all interfaces to prevent spoofing attacks B) Uncomment the next line to enable packet forwarding for IPv4 C) Uncomment the next line to enable packet forwarding for IPv6 D) Do no accept ICMP redirects (we are not a router) E) Accept ICMP redirects only for gateways listed in our default gateway list F) Do not send ICMP redirects G) Do not accept IP source route packets (we are not a router) H) Log Martian Packets 4) Configure the passwd file Replace "sh" by "false" for all accounts except user account and root. I also did it for the account called sshd. I am not sure whether it will prevent SSH connection (which I want to use) or if it's something else. 5) Configure the shadow file In the console: passwd -l to lock all accounts except user account. 6) Install rkhunter and chkrootkit 7) Install Bum Disabled those services: "High performance mail server", "unreadable (kerneloops)","unreadable (speech-dispatcher)","Restores DNS" (should this one stay on?) 8) Install Apparmor_profiles 9) Install clamav & freshclam (antivirus and update) What did I do wrong and what should I do more to secure this Linux machine? Thanks a lot in advance

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• Configure server on network to analyze traffic

  - by Strajan Sebastian

  I have the following network: http://i.stack.imgur.com/rapkH.jpg I want to send all the traffic from the devices that connect to the 192.168.0.1 router to the 192.168.10.1 router(and eventually to the Internet), by passing through the server and an additional router. Almost 2 days have passed and I can't figure what is wrong. While searching on the Internet for some similar configuration I found some articles that are somehow related to my needs, but the proposed solutions don't seem to work for me. This is a similar article: iptables forwarding between two interface I done the following steps for the configuration process: Set static IP address 192.168.1.90 for the eth0 on the server from the 192.168.1.1 router Set static IP address 192.168.0.90 for the eth1 on the server from the 192.168.0.1 router Forwarded all the traffic from 192.168.0.1 router to the server on eth1 interface witch seems to be working. The router firmware has some option to redirect all the traffic from all the ports to a specified address. Added the following rules on the server(Only the following, there aren't any additional rules): iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE iptables -A FORWARD -i eth1 -o eth0 -m state -–state RELATED,ESTABLISHED -j ACCEPT iptables -A FORWARD -i eth0 -o eth1 -j ACCEPT I also tried changing iptables -A FORWARD -i eth1 -o eth0 -m state -–state RELATED,ESTABLISHED -j ACCEPT into iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT but still is not working. After adding the following to enable the packet forwarding for the server that is running CentOS: echo 1 /proc/sys/net/ipv4/ip_forward sysctl -w net.ipv4.ip_forward = 1 After a server restart and extra an extra check to see that all the configuration from above are still available I tried to see again if I can ping from a computer connected to 192.168.0.1/24 LAN the router from 192.168.1.1 but it didn't worked. The server has tshark(console wireshark) installed and I found that while sending a ping from a computer connected to 192.168.0.1 router to 192.168.1.1 the 192.168.0.90(eth1) receives the ping but it doesn't forward it to the eth0 interface as the rule tells: iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT and don't now why this is happening. Questions: The iptables seem that don't work as I am expecting. Is there a need to add in the NAT table from iptables rules to redirect the traffic to the proper location, or is something else wrong with what I've done? I want to use tshark to view the traffic on the server because I think that is the best at doing this. Do you know something better that tshark to capture the traffic and maybe analyze it?

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• Coherence Warnings in WLS

  - by john.graves(at)oracle.com

  With 11g (10.3.4 WLS), coherence is now built into many applications.  I’ve been noticing errors in my OSB logs like these:####<10/03/2011 10:45:40 AM EST> <Warning> <Coherence> <osb-jeos> <osb_server1> <Logger@324239121 3.6.0.4> <<anonymous>> <> <583c1 0bfdbd326ba:-8c38159:12e9d02c829:-8000-0000000000000003> <1299714340643> <BEA-000000> <Oracle Coherence 3.6.0.4 (member=n/a): Unic astUdpSocket failed to set receive buffer size to 714 packets (1023KB); actual size is 12%, 89 packets (127KB). Consult your OS do cumentation regarding increasing the maximum socket buffer size. Proceeding with the actual value may cause sub-optimal performanc e.> ####<10/03/2011 10:45:40 AM EST> <Warning> <Coherence> <osb-jeos> <osb_server1> <Logger@324239121 3.6.0.4> <<anonymous>> <> <583c1 0bfdbd326ba:-8c38159:12e9d02c829:-8000-0000000000000003> <1299714340650> <BEA-000000> <Oracle Coherence 3.6.0.4 (member=n/a): Pref erredUnicastUdpSocket failed to set receive buffer size to 1428 packets (1.99MB); actual size is 6%, 89 packets (127KB). Consult y our OS documentation regarding increasing the maximum socket buffer size. Proceeding with the actual value may cause sub-optimal p erformance.> ####<10/03/2011 10:45:40 AM EST> <Warning> <Coherence> <osb-jeos> <osb_server1> <Logger@324239121 3.6.0.4> <<anonymous>> <> <583c1 0bfdbd326ba:-8c38159:12e9d02c829:-8000-0000000000000003> <1299714340659> <BEA-000000> <Oracle Coherence 3.6.0.4 (member=n/a): Mult icastUdpSocket failed to set receive buffer size to 714 packets (1023KB); actual size is 12%, 89 packets (127KB). Consult your OS documentation regarding increasing the maximum socket buffer size. Proceeding with the actual value may cause sub-optimal performa nce.> I was able to “fix” this on my ubuntu system by adding the following lines to the /etc/sysctl.conf file:# Setup networking for coherence # maximum receive socket buffer size, default 131071 net.core.rmem_max = 2000000 # maximum send socket buffer size, default 131071 net.core.wmem_max = 1000000 # default receive socket buffer size, default 65535 net.core.rmem_default = 2524287 # default send socket buffer size, default 65535 net.core.wmem_default = 2524287 .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }

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• Rkhunter 122 suspect files; do I have a problem?

  - by user276166

  I am new to ubuntu. I am using Xfce Ubuntu 14.04 LTS. I have ran rkhunter a few weeks age and only got a few warnings. The forum said that they were normal. But, this time rkhunter reported 122 warnings. Please advise. casey@Shaman:~$ sudo rkhunter -c [ Rootkit Hunter version 1.4.0 ] Checking system commands... Performing 'strings' command checks Checking 'strings' command [ OK ] Performing 'shared libraries' checks Checking for preloading variables [ None found ] Checking for preloaded libraries [ None found ] Checking LD_LIBRARY_PATH variable [ Not found ] Performing file properties checks Checking for prerequisites [ Warning ] /usr/sbin/adduser [ Warning ] /usr/sbin/chroot [ Warning ] /usr/sbin/cron [ OK ] /usr/sbin/groupadd [ Warning ] /usr/sbin/groupdel [ Warning ] /usr/sbin/groupmod [ Warning ] /usr/sbin/grpck [ Warning ] /usr/sbin/nologin [ Warning ] /usr/sbin/pwck [ Warning ] /usr/sbin/rsyslogd [ Warning ] /usr/sbin/useradd [ Warning ] /usr/sbin/userdel [ Warning ] /usr/sbin/usermod [ Warning ] /usr/sbin/vipw [ Warning ] /usr/bin/awk [ Warning ] /usr/bin/basename [ Warning ] /usr/bin/chattr [ Warning ] /usr/bin/cut [ Warning ] /usr/bin/diff [ Warning ] /usr/bin/dirname [ Warning ] /usr/bin/dpkg [ Warning ] /usr/bin/dpkg-query [ Warning ] /usr/bin/du [ Warning ] /usr/bin/env [ Warning ] /usr/bin/file [ Warning ] /usr/bin/find [ Warning ] /usr/bin/GET [ Warning ] /usr/bin/groups [ Warning ] /usr/bin/head [ Warning ] /usr/bin/id [ Warning ] /usr/bin/killall [ OK ] /usr/bin/last [ Warning ] /usr/bin/lastlog [ Warning ] /usr/bin/ldd [ Warning ] /usr/bin/less [ OK ] /usr/bin/locate [ OK ] /usr/bin/logger [ Warning ] /usr/bin/lsattr [ Warning ] /usr/bin/lsof [ OK ] /usr/bin/mail [ OK ] /usr/bin/md5sum [ Warning ] /usr/bin/mlocate [ OK ] /usr/bin/newgrp [ Warning ] /usr/bin/passwd [ Warning ] /usr/bin/perl [ Warning ] /usr/bin/pgrep [ Warning ] /usr/bin/pkill [ Warning ] /usr/bin/pstree [ OK ] /usr/bin/rkhunter [ OK ] /usr/bin/rpm [ Warning ] /usr/bin/runcon [ Warning ] /usr/bin/sha1sum [ Warning ] /usr/bin/sha224sum [ Warning ] /usr/bin/sha256sum [ Warning ] /usr/bin/sha384sum [ Warning ] /usr/bin/sha512sum [ Warning ] /usr/bin/size [ Warning ] /usr/bin/sort [ Warning ] /usr/bin/stat [ Warning ] /usr/bin/strace [ Warning ] /usr/bin/strings [ Warning ] /usr/bin/sudo [ Warning ] /usr/bin/tail [ Warning ] /usr/bin/test [ Warning ] /usr/bin/top [ Warning ] /usr/bin/touch [ Warning ] /usr/bin/tr [ Warning ] /usr/bin/uniq [ Warning ] /usr/bin/users [ Warning ] /usr/bin/vmstat [ Warning ] /usr/bin/w [ Warning ] /usr/bin/watch [ Warning ] /usr/bin/wc [ Warning ] /usr/bin/wget [ Warning ] /usr/bin/whatis [ Warning ] /usr/bin/whereis [ Warning ] /usr/bin/which [ OK ] /usr/bin/who [ Warning ] /usr/bin/whoami [ Warning ] /usr/bin/unhide.rb [ Warning ] /usr/bin/mawk [ Warning ] /usr/bin/lwp-request [ Warning ] /usr/bin/heirloom-mailx [ OK ] /usr/bin/w.procps [ Warning ] /sbin/depmod [ Warning ] /sbin/fsck [ Warning ] /sbin/ifconfig [ Warning ] /sbin/ifdown [ Warning ] /sbin/ifup [ Warning ] /sbin/init [ Warning ] /sbin/insmod [ Warning ] /sbin/ip [ Warning ] /sbin/lsmod [ Warning ] /sbin/modinfo [ Warning ] /sbin/modprobe [ Warning ] /sbin/rmmod [ Warning ] /sbin/route [ Warning ] /sbin/runlevel [ Warning ] /sbin/sulogin [ Warning ] /sbin/sysctl [ Warning ] /bin/bash [ Warning ] /bin/cat [ Warning ] /bin/chmod [ Warning ] /bin/chown [ Warning ] /bin/cp [ Warning ] /bin/date [ Warning ] /bin/df [ Warning ] /bin/dmesg [ Warning ] /bin/echo [ Warning ] /bin/ed [ OK ] /bin/egrep [ Warning ] /bin/fgrep [ Warning ] /bin/fuser [ OK ] /bin/grep [ Warning ] /bin/ip [ Warning ] /bin/kill [ Warning ] /bin/less [ OK ] /bin/login [ Warning ] /bin/ls [ Warning ] /bin/lsmod [ Warning ] /bin/mktemp [ Warning ] /bin/more [ Warning ] /bin/mount [ Warning ] /bin/mv [ Warning ] /bin/netstat [ Warning ] /bin/ping [ Warning ] /bin/ps [ Warning ] /bin/pwd [ Warning ] /bin/readlink [ Warning ] /bin/sed [ Warning ] /bin/sh [ Warning ] /bin/su [ Warning ] /bin/touch [ Warning ] /bin/uname [ Warning ] /bin/which [ OK ] /bin/kmod [ Warning ] /bin/dash [ Warning ] [Press <ENTER> to continue] Checking for rootkits... Performing check of known rootkit files and directories 55808 Trojan - Variant A [ Not found ] ADM Worm [ Not found ] AjaKit Rootkit [ Not found ] Adore Rootkit [ Not found ] aPa Kit [ Not found ] Apache Worm [ Not found ] Ambient (ark) Rootkit [ Not found ] Balaur Rootkit [ Not found ] BeastKit Rootkit [ Not found ] beX2 Rootkit [ Not found ] BOBKit Rootkit [ Not found ] cb Rootkit [ Not found ] CiNIK Worm (Slapper.B variant) [ Not found ] Danny-Boy's Abuse Kit [ Not found ] Devil RootKit [ Not found ] Dica-Kit Rootkit [ Not found ] Dreams Rootkit [ Not found ] Duarawkz Rootkit [ Not found ] Enye LKM [ Not found ] Flea Linux Rootkit [ Not found ] Fu Rootkit [ Not found ] Fuck`it Rootkit [ Not found ] GasKit Rootkit [ Not found ] Heroin LKM [ Not found ] HjC Kit [ Not found ] ignoKit Rootkit [ Not found ] IntoXonia-NG Rootkit [ Not found ] Irix Rootkit [ Not found ] Jynx Rootkit [ Not found ] KBeast Rootkit [ Not found ] Kitko Rootkit [ Not found ] Knark Rootkit [ Not found ] ld-linuxv.so Rootkit [ Not found ] Li0n Worm [ Not found ] Lockit / LJK2 Rootkit [ Not found ] Mood-NT Rootkit [ Not found ] MRK Rootkit [ Not found ] Ni0 Rootkit [ Not found ] Ohhara Rootkit [ Not found ] Optic Kit (Tux) Worm [ Not found ] Oz Rootkit [ Not found ] Phalanx Rootkit [ Not found ] Phalanx2 Rootkit [ Not found ] Phalanx2 Rootkit (extended tests) [ Not found ] Portacelo Rootkit [ Not found ] R3dstorm Toolkit [ Not found ] RH-Sharpe's Rootkit [ Not found ] RSHA's Rootkit [ Not found ] Scalper Worm [ Not found ] Sebek LKM [ Not found ] Shutdown Rootkit [ Not found ] SHV4 Rootkit [ Not found ] SHV5 Rootkit [ Not found ] Sin Rootkit [ Not found ] Slapper Worm [ Not found ] Sneakin Rootkit [ Not found ] 'Spanish' Rootkit [ Not found ] Suckit Rootkit [ Not found ] Superkit Rootkit [ Not found ] TBD (Telnet BackDoor) [ Not found ] TeLeKiT Rootkit [ Not found ] T0rn Rootkit [ Not found ] trNkit Rootkit [ Not found ] Trojanit Kit [ Not found ] Tuxtendo Rootkit [ Not found ] URK Rootkit [ Not found ] Vampire Rootkit [ Not found ] VcKit Rootkit [ Not found ] Volc Rootkit [ Not found ] Xzibit Rootkit [ Not found ] zaRwT.KiT Rootkit [ Not found ] ZK Rootkit [ Not found ] [Press <ENTER> to continue] Performing additional rootkit checks Suckit Rookit additional checks [ OK ] Checking for possible rootkit files and directories [ None found ] Checking for possible rootkit strings [ None found ] Performing malware checks Checking running processes for suspicious files [ None found ] Checking for login backdoors [ None found ] Checking for suspicious directories [ None found ] Checking for sniffer log files [ None found ] Performing Linux specific checks Checking loaded kernel modules [ OK ] Checking kernel module names [ OK ] [Press <ENTER> to continue] Checking the network... Performing checks on the network ports Checking for backdoor ports [ None found ] Checking for hidden ports [ Skipped ] Performing checks on the network interfaces Checking for promiscuous interfaces [ None found ] Checking the local host... Performing system boot checks Checking for local host name [ Found ] Checking for system startup files [ Found ] Checking system startup files for malware [ None found ] Performing group and account checks Checking for passwd file [ Found ] Checking for root equivalent (UID 0) accounts [ None found ] Checking for passwordless accounts [ None found ] Checking for passwd file changes [ Warning ] Checking for group file changes [ Warning ] Checking root account shell history files [ None found ] Performing system configuration file checks Checking for SSH configuration file [ Not found ] Checking for running syslog daemon [ Found ] Checking for syslog configuration file [ Found ] Checking if syslog remote logging is allowed [ Not allowed ] Performing filesystem checks Checking /dev for suspicious file types [ Warning ] Checking for hidden files and directories [ Warning ] [Press <ENTER> to continue] System checks summary ===================== File properties checks... Required commands check failed Files checked: 137 Suspect files: 122 Rootkit checks... Rootkits checked : 291 Possible rootkits: 0 Applications checks... All checks skipped The system checks took: 5 minutes and 11 seconds All results have been written to the log file (/var/log/rkhunter.log)

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• ufw portforwarding to virtualbox guest

  - by user85116

  My goal is to be able to connect using remote desktop on my desktop machine, to windows xp running in virtualbox on my linux server. My setup: server = debian squeeze, 64 bit, with a public IP address (host) virtualbox-ose 3.2.10 (from debian repo) windows xp running inside VBox as a guest; bridged networking mode in VBox, ip = 192.168.1.100 ufw as the firewall on debian, 3 ports are opened: 22 / ssh, 80 / apache, and 3389 for remote desktop My problem: If I try to use remote desktop on my home computer, I am unable to connect to the windows guest. If I first "ssh -X -C" into the debian server, then run "rdesktop 192.168.1.100", I am able to connect without issue. The windows firewall was configured to allow remote desktop connections, and I've even turned it off (as it is redundant here) to see if that was the problem but it made no difference. Since I am able to connect from inside the local subnet, I suspect that I have not setup my debian firewall correctly to handle connections from outside the LAN. Here is what I've done... First my ufw status: ufw status Status: active To Action From -- ------ ---- 22 ALLOW Anywhere 80 ALLOW Anywhere 3389 ALLOW Anywhere I edited /etc/ufw/sysctl.conf and added: net/ipv4/ip_forward=1 Edited /etc/default/ufw and added: DEFAULT_FORWARD_POLICY="ACCEPT" Edited /etc/ufw/before.rules and added: # setup port forwarding to forward rdp to windows VM *nat :PREROUTING - [0:0] -A PREROUTING -i eth0 -p tcp --dport 3389 -j DNAT --to-destination 192.168.1.100 -A PREROUTING -i eth0 -p udp --dport 3389 -j DNAT --to-destination 192.168.1.100 COMMIT # Don't delete these required lines, otherwise there will be errors *filter <snip> Restarted the firewall etc., but no connection. My log files on the debian host show this (my public ip address was removed for this posting but it is correct in the actual log): Feb 6 11:11:21 localhost kernel: [171991.856941] [UFW AUDIT] IN=eth0 OUT=eth0 SRC=aaa.bbb.ccc.dd DST=192.168.1.100 LEN=60 TOS=0x00 PREC=0x00 TTL=45 ID=27518 DF PROTO=TCP SPT=54201 DPT=3389 WINDOW=5840 RES=0x00 SYN URGP=0 Feb 6 11:11:21 localhost kernel: [171991.856963] [UFW ALLOW] IN=eth0 OUT=eth0 SRC=aaa.bbb.ccc.dd DST=192.168.1.100 LEN=60 TOS=0x00 PREC=0x00 TTL=45 ID=27518 DF PROTO=TCP SPT=54201 DPT=3389 WINDOW=5840 RES=0x00 SYN URGP=0 Feb 6 11:11:24 localhost kernel: [171994.856701] [UFW AUDIT] IN=eth0 OUT=eth0 SRC=aaa.bbb.ccc.dd DST=192.168.1.100 LEN=60 TOS=0x00 PREC=0x00 TTL=45 ID=27519 DF PROTO=TCP SPT=54201 DPT=3389 WINDOW=5840 RES=0x00 SYN URGP=0 Feb 6 11:11:24 localhost kernel: [171994.856723] [UFW ALLOW] IN=eth0 OUT=eth0 SRC=aaa.bbb.ccc.dd DST=192.168.1.100 LEN=60 TOS=0x00 PREC=0x00 TTL=45 ID=27519 DF PROTO=TCP SPT=54201 DPT=3389 WINDOW=5840 RES=0x00 SYN URGP=0 Feb 6 11:11:30 localhost kernel: [172000.856656] [UFW AUDIT] IN=eth0 OUT=eth0 SRC=aaa.bbb.ccc.dd DST=192.168.1.100 LEN=60 TOS=0x00 PREC=0x00 TTL=45 ID=27520 DF PROTO=TCP SPT=54201 DPT=3389 WINDOW=5840 RES=0x00 SYN URGP=0 Feb 6 11:11:30 localhost kernel: [172000.856678] [UFW ALLOW] IN=eth0 OUT=eth0 SRC=aaa.bbb.ccc.dd DST=192.168.1.100 LEN=60 TOS=0x00 PREC=0x00 TTL=45 ID=27520 DF PROTO=TCP SPT=54201 DPT=3389 WINDOW=5840 RES=0x00 SYN URGP=0 Although this is the current setup / configuration, I've also tried several variations of this; I thought maybe the ISP would be blocking 3389 for some reason and tried using different ports, but again there was no connection. Any ideas...? Did I forget to modify some file somewhere?

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• Can't launch glassfish on ec2 - can't open port

  - by orange80

  I'm trying to start glassfish on an EBS-based AMI of Ubuntu 10.04 64-bit. I have used glassfish on non-ec2 servers with no problems, but on ec2 I get this message: $ sudo -u glassfish bin/asadmin start-domain domain1 There is a process already using the admin port 4848 -- it probably is another instance of a GlassFish server. Command start-domain failed. I know that ec2 has requires that firewall rules be modified using ec2-authorize to let outside traffic thru the firewall, as I had to do to make ssh work. This still doesn't explain the port error when all I'm trying to do is start glassfish so I can try $ wget localhost:8080and make sure it's working. This is very frustrating and I'd really appreciate any help. Thanks. FINAL UPDATE: Sorry if you came here looking for answers. I never figured out what was causing the problem. I created another fresh instance, installed the same stuff, and Glassfish worked perfectly. Something obviously got boned during installation, but I have no idea what. I guess it will remain a mystery. UPDATE: Here's what I get from netstat: # netstat -nuptl Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 462/sshd tcp6 0 0 :::22 :::* LISTEN 462/sshd udp 0 0 0.0.0.0:5353 0.0.0.0:* 483/avahi-daemon: r udp 0 0 0.0.0.0:1194 0.0.0.0:* 589/openvpn udp 0 0 0.0.0.0:37940 0.0.0.0:* 483/avahi-daemon: r udp 0 0 0.0.0.0:68 0.0.0.0:* 377/dhclient3 UPDATE: One more thing... I know that the "net.ipv6.bindv6only" kernel option can cause problems with java networking, so I did set this: # sysctl -w net.ipv6.bindv6only=0 UPDATE: I also verified that it has nothing at all to do with the port number (4848). As you can see here, when I changed the admin-listener port in domain.xml to 4949, I get a similar message: # sudo -u glassfish bin/asadmin start-domain domain1 There is a process already using the admin port 4949 -- it probably is another instance of a GlassFish server. Command start-domain failed. UPDATE: Here are the contents of /etc/hosts: 127.0.0.1 localhost # The following lines are desirable for IPv6 capable hosts ::1 ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters ff02::3 ip6-allhosts I should mention that I have another Ubuntu Lucid 10.04 64-bit slice that is NOT hosted on ec2, and set it up the exact same way with no problems whatsoever. Also server.log doesn't offer much insight either: # cat ./server.log Nov 20, 2010 8:46:49 AM com.sun.enterprise.admin.launcher.GFLauncherLogger info INFO: JVM invocation command line: /usr/lib/jvm/java-6-sun-1.6.0.22/bin/java -cp /opt/glassfishv3/glassfish/modules/glassfish.jar -XX:+UnlockDiagnosticVMOptions -XX:MaxPermSize=192m -XX:NewRatio=2 -XX:+LogVMOutput -XX:LogFile=/opt/glassfishv3/glassfish/domains/domain1/logs/jvm.log -Xmx512m -client -javaagent:/opt/glassfishv3/glassfish/lib/monitor/btrace-agent.jar=unsafe=true,noServer=true -Dosgi.shell.telnet.maxconn=1 -Djdbc.drivers=org.apache.derby.jdbc.ClientDriver -Dfelix.fileinstall.dir=/opt/glassfishv3/glassfish/modules/autostart/ -Djavax.net.ssl.keyStore=/opt/glassfishv3/glassfish/domains/domain1/config/keystore.jks -Dosgi.shell.telnet.port=6666 -Djava.security.policy=/opt/glassfishv3/glassfish/domains/domain1/config/server.policy -Dfelix.fileinstall.poll=5000 -Dcom.sun.aas.instanceRoot=/opt/glassfishv3/glassfish/domains/domain1 -Dcom.sun.enterprise.config.config_environment_factory_class=com.sun.enterprise.config.serverbeans.AppserverConfigEnvironmentFactory -Dosgi.shell.telnet.ip=127.0.0.1 -Djava.endorsed.dirs=/opt/glassfishv3/glassfish/modules/endorsed:/opt/glassfishv3/glassfish/lib/endorsed -Dcom.sun.aas.installRoot=/opt/glassfishv3/glassfish -Djava.ext.dirs=/usr/lib/jvm/java-6-sun-1.6.0.22/lib/ext:/usr/lib/jvm/java-6-sun-1.6.0.22/jre/lib/ext:/opt/glassfishv3/glassfish/domains/domain1/lib/ext -Dfelix.fileinstall.bundles.new.start=true -Djavax.net.ssl.trustStore=/opt/glassfishv3/glassfish/domains/domain1/config/cacerts.jks -Dcom.sun.enterprise.security.httpsOutboundKeyAlias=s1as -Djava.security.auth.login.config=/opt/glassfishv3/glassfish/domains/domain1/config/login.conf -DANTLR_USE_DIRECT_CLASS_LOADING=true -Dfelix.fileinstall.debug=1 -Dorg.glassfish.web.rfc2109_cookie_names_enforced=false -Djava.library.path=/opt/glassfishv3/glassfish/lib:/usr/lib/jvm/java-6-sun-1.6.0.22/jre/lib/amd64/server:/usr/lib/jvm/java-6-sun-1.6.0.22/jre/lib/amd64:/usr/lib/jvm/java-6-sun-1.6.0.22/lib/amd64:/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib com.sun.enterprise.glassfish.bootstrap.ASMain -domainname domain1 -asadmin-args start-domain,,,domain1 -instancename server -verbose false -debug false -asadmin-classpath /opt/glassfishv3/glassfish/modules/admin-cli.jar -asadmin-classname com.sun.enterprise.admin.cli.AsadminMain -upgrade false -domaindir /opt/glassfishv3/glassfish/domains/domain1 -read-stdin true

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• UFW as an active service on Ubuntu

  - by lamcro

  Every time I restart my computer, and check the status of the UFW firewall (sudo ufw status), it is disabled, even if I then enable and restart it. I tried putting sudo ufw enable as one of the startup applications but it asks for the sudo password every time I log on, and I'm guessing it does not protect anyone else who logs on my computer. How can I setup ufw so it is activated when I turn on my computer, and protects all accounts? Update I just tried /etc/init.d/ufw start, and it activated the firewall. Then I restarted the computer, and again it was disabled. content of /etc/ufw/ufw.conf # /etc/ufw/ufw.conf # # set to yes to start on boot ENABLED=yes # set to one of 'off', 'low', 'medium', 'high' LOGLEVEL=full content of /etc/default/ufw # /etc/default/ufw # # Set to yes to apply rules to support IPv6 (no means only IPv6 on loopback # accepted). You will need to 'disable' and then 'enable' the firewall for # the changes to take affect. IPV6=no # Set the default input policy to ACCEPT, ACCEPT_NO_TRACK, DROP, or REJECT. # ACCEPT enables connection tracking for NEW inbound packets on the INPUT # chain, whereas ACCEPT_NO_TRACK does not use connection tracking. Please note # that if you change this you will most likely want to adjust your rules. DEFAULT_INPUT_POLICY="DROP" # Set the default output policy to ACCEPT, ACCEPT_NO_TRACK, DROP, or REJECT. # ACCEPT enables connection tracking for NEW outbound packets on the OUTPUT # chain, whereas ACCEPT_NO_TRACK does not use connection tracking. Please note # that if you change this you will most likely want to adjust your rules. DEFAULT_OUTPUT_POLICY="ACCEPT" # Set the default forward policy to ACCEPT, DROP or REJECT. Please note that # if you change this you will most likely want to adjust your rules DEFAULT_FORWARD_POLICY="DROP" # Set the default application policy to ACCEPT, DROP, REJECT or SKIP. Please # note that setting this to ACCEPT may be a security risk. See 'man ufw' for # details DEFAULT_APPLICATION_POLICY="SKIP" # By default, ufw only touches its own chains. Set this to 'yes' to have ufw # manage the built-in chains too. Warning: setting this to 'yes' will break # non-ufw managed firewall rules MANAGE_BUILTINS=no # # IPT backend # # only enable if using iptables backend IPT_SYSCTL=/etc/ufw/sysctl.conf # extra connection tracking modules to load IPT_MODULES="nf_conntrack_ftp nf_nat_ftp nf_conntrack_irc nf_nat_irc" Update Followed your advise and ran update-rc.d with no luck. lester@mcgrath-pc:~$ sudo update-rc.d ufw defaults update-rc.d: warning: /etc/init.d/ufw missing LSB information update-rc.d: see <http://wiki.debian.org/LSBInitScripts> Adding system startup for /etc/init.d/ufw ... /etc/rc0.d/K20ufw -> ../init.d/ufw /etc/rc1.d/K20ufw -> ../init.d/ufw /etc/rc6.d/K20ufw -> ../init.d/ufw /etc/rc2.d/S20ufw -> ../init.d/ufw /etc/rc3.d/S20ufw -> ../init.d/ufw /etc/rc4.d/S20ufw -> ../init.d/ufw /etc/rc5.d/S20ufw -> ../init.d/ufw lester@mcgrath-pc:~$ ls -l /etc/rc?.d/*ufw lrwxrwxrwx 1 root root 13 2009-12-20 20:34 /etc/rc0.d/K20ufw -> ../init.d/ufw lrwxrwxrwx 1 root root 13 2009-12-20 20:34 /etc/rc1.d/K20ufw -> ../init.d/ufw lrwxrwxrwx 1 root root 13 2009-12-20 20:34 /etc/rc2.d/S20ufw -> ../init.d/ufw lrwxrwxrwx 1 root root 13 2009-12-20 20:34 /etc/rc3.d/S20ufw -> ../init.d/ufw lrwxrwxrwx 1 root root 13 2009-12-20 20:34 /etc/rc4.d/S20ufw -> ../init.d/ufw lrwxrwxrwx 1 root root 13 2009-12-20 20:34 /etc/rc5.d/S20ufw -> ../init.d/ufw lrwxrwxrwx 1 root root 13 2009-12-20 20:34 /etc/rc6.d/K20ufw -> ../init.d/ufw

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• Neighbour table overflow on Linux hosts related to bridging and ipv6

  - by tim

  Note: I already have a workaround for this problem (as described below) so this is only a "want-to-know" question. I have a productive setup with around 50 hosts including blades running xen 4 and equallogics providing iscsi. All xen dom0s are almost plain Debian 5. The setup includes several bridges on every dom0 to support xen bridged networking. In total there are between 5 and 12 bridges on each dom0 servicing one vlan each. None of the hosts has routing enabled. At one point in time we moved one of the machines to a new hardware including a raid controller and so we installed an upstream 3.0.22/x86_64 kernel with xen patches. All other machines run debian xen-dom0-kernel. Since then we noticed on all hosts in the setup the following errors every ~2 minutes: [55888.881994] __ratelimit: 908 callbacks suppressed [55888.882221] Neighbour table overflow. [55888.882476] Neighbour table overflow. [55888.882732] Neighbour table overflow. [55888.883050] Neighbour table overflow. [55888.883307] Neighbour table overflow. [55888.883562] Neighbour table overflow. [55888.883859] Neighbour table overflow. [55888.884118] Neighbour table overflow. [55888.884373] Neighbour table overflow. [55888.884666] Neighbour table overflow. The arp table (arp -n) never showed more than around 20 entries on every machine. We tried the obvious tweaks and raised the /proc/sys/net/ipv4/neigh/default/gc_thresh* values. FInally to 16384 entries but no effect. Not even the interval of ~2 minutes changed which lead me to the conclusion that this is totally unrelated. tcpdump showed no uncommon ipv4 traffic on any interface. The only interesting finding from tcpdump were ipv6 packets bursting in like: 14:33:13.137668 IP6 fe80::216:3eff:fe1d:9d01 > ff02::1:ff1d:9d01: HBH ICMP6, multicast listener reportmax resp delay: 0 addr: ff02::1:ff1d:9d01, length 24 14:33:13.138061 IP6 fe80::216:3eff:fe1d:a8c1 > ff02::1:ff1d:a8c1: HBH ICMP6, multicast listener reportmax resp delay: 0 addr: ff02::1:ff1d:a8c1, length 24 14:33:13.138619 IP6 fe80::216:3eff:fe1d:bf81 > ff02::1:ff1d:bf81: HBH ICMP6, multicast listener reportmax resp delay: 0 addr: ff02::1:ff1d:bf81, length 24 14:33:13.138974 IP6 fe80::216:3eff:fe1d:eb41 > ff02::1:ff1d:eb41: HBH ICMP6, multicast listener reportmax resp delay: 0 addr: ff02::1:ff1d:eb41, length 24 which placed the idea in my mind that the problem maybe related to ipv6, since we have no ipv6 services in this setup. The only other hint was the coincidence of the host upgrade with the beginning of the problems. I powered down the host in question and the errors were gone. Then I subsequently took down the bridges on the host and when i took down (ifconfig down) one particularly bridge: br-vlan2159 Link encap:Ethernet HWaddr 00:26:b9:fb:16:2c inet6 addr: fe80::226:b9ff:fefb:162c/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:120 errors:0 dropped:0 overruns:0 frame:0 TX packets:9 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:5286 (5.1 KiB) TX bytes:726 (726.0 B) eth0.2159 Link encap:Ethernet HWaddr 00:26:b9:fb:16:2c inet6 addr: fe80::226:b9ff:fefb:162c/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:1801 errors:0 dropped:0 overruns:0 frame:0 TX packets:20 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:126228 (123.2 KiB) TX bytes:1464 (1.4 KiB) bridge name bridge id STP enabled interfaces ... br-vlan2158 8000.0026b9fb162c no eth0.2158 br-vlan2159 8000.0026b9fb162c no eth0.2159 The errors went away again. As you can see the bridge holds no ipv4 address and it's only member is eth0.2159 so no traffic should cross it. Bridge and interface .2159 / .2157 / .2158 which are in all aspects identical apart from the vlan they are connected to had no effect when taken down. Now I disabled ipv6 on the entire host via sysctl net.ipv6.conf.all.disable_ipv6 and rebooted. After this even with bridge br-vlan2159 enabled no errors occur. Any ideas are welcome.

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• Long connection times from PHP to MySQL on EC2

  - by Erik Giberti

  I'm having an intermittent issue connecting to a database slave with InnoDB. Intermittently I get connections taking longer than 2 seconds. These servers are hosted on Amazon's EC2. The app server is PHP 5.2/Apache running on Ubuntu. The DB slave is running Percona's XtraDB 5.1 on Ubuntu 9.10. It's using an EBS Raid array for the data storage. We already use skip name resolve and bind to address 0.0.0.0. This is a stub of the PHP code that's failing $tmp = mysqli_init(); $start_time = microtime(true); $tmp-options(MYSQLI_OPT_CONNECT_TIMEOUT, 2); $tmp-real_connect($DB_SERVERS[$server]['server'], $DB_SERVERS[$server]['username'], $DB_SERVERS[$server]['password'], $DB_SERVERS[$server]['schema'], $DB_SERVERS[$server]['port']); if(mysqli_connect_errno()){ $timer = microtime(true) - $start_time; mail($errors_to,'DB connection error',$timer); } There's more than 300Mb available on the DB server for new connections and the server is nowhere near the max allowed (60 of 1,200). Loading on both servers is < 2 on 4 core m1.xlarge instances. Some highlights from the mysql config max_connections = 1200 thread_stack = 512K thread_cache_size = 1024 thread_concurrency = 16 innodb-file-per-table innodb_additional_mem_pool_size = 16M innodb_buffer_pool_size = 13G Any help on tracing the source of the slowdown is appreciated. [EDIT] I have been updating the sysctl values for the network but they don't seem to be fixing the problem. I made the following adjustments on both the database and application servers. net.ipv4.tcp_window_scaling = 1 net.ipv4.tcp_sack = 0 net.ipv4.tcp_timestamps = 0 net.ipv4.tcp_fin_timeout = 20 net.ipv4.tcp_keepalive_time = 180 net.ipv4.tcp_max_syn_backlog = 1280 net.ipv4.tcp_synack_retries = 1 net.core.rmem_max = 16777216 net.core.wmem_max = 16777216 net.ipv4.tcp_rmem = 4096 87380 16777216 net.ipv4.tcp_wmem = 4096 87380 16777216 [EDIT] Per jaimieb's suggestion, I added some tracing and captured the following data using time. This server handles about 51 queries/second at this the time of day. The connection error was raised once (at 13:06:36) during the 3 minute window outlined below. Since there was 1 failure and roughly 9,200 successful connections, I think this isn't going to produce anything meaningful in terms of reporting. Script: date /root/database_server.txt (time mysql -h database_Server -D schema_name -u appuser -p apppassword -e '') /dev/null 2 /root/database_server.txt Results: === Application Server 1 === Mon Feb 22 13:05:01 EST 2010 real 0m0.008s user 0m0.001s sys 0m0.000s Mon Feb 22 13:06:01 EST 2010 real 0m0.007s user 0m0.002s sys 0m0.000s Mon Feb 22 13:07:01 EST 2010 real 0m0.008s user 0m0.000s sys 0m0.001s === Application Server 2 === Mon Feb 22 13:05:01 EST 2010 real 0m0.009s user 0m0.000s sys 0m0.002s Mon Feb 22 13:06:01 EST 2010 real 0m0.009s user 0m0.001s sys 0m0.003s Mon Feb 22 13:07:01 EST 2010 real 0m0.008s user 0m0.000s sys 0m0.001s === Database Server === Mon Feb 22 13:05:01 EST 2010 real 0m0.016s user 0m0.000s sys 0m0.010s Mon Feb 22 13:06:01 EST 2010 real 0m0.006s user 0m0.010s sys 0m0.000s Mon Feb 22 13:07:01 EST 2010 real 0m0.016s user 0m0.000s sys 0m0.010s [EDIT] Per a suggestion received on a LinkedIn question, I tried setting the back_log value higher. We had been running the default value (50) and increased it to 150. We also raised the kernel value /proc/sys/net/core/somaxconn (maximum socket connections) to 256 on both the application and database server from the default 128. We did see some elevation in processor utilization as a result but still received connection timeouts.

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• Amazon EC2 Instance - m1.medium Ubuntu 12.04 - Started to crash three days ago

  - by Joy

  The environment: Amazon EC2 Instance - m1.medium Ubuntu 12.04 Apache 2.2.22 - Running a Drupal Site Using MySQL DB Server RAM info: ~$ free -gt total used free shared buffers cached Mem: 3 1 2 0 0 0 -/+ buffers/cache: 0 2 Swap: 0 0 0 Total: 3 1 2 Hard drive info: Filesystem Size Used Avail Use% Mounted on /dev/xvda1 7.9G 4.7G 2.9G 62% / udev 1.9G 8.0K 1.9G 1% /dev tmpfs 751M 180K 750M 1% /run none 5.0M 0 5.0M 0% /run/lock none 1.9G 0 1.9G 0% /run/shm /dev/xvdb 394G 199M 374G 1% /mnt The problem About two days ago the site started failing becaue the MySQL server was shut down by Apache with the following message: kernel: [2963685.664359] [31716] 106 31716 226946 22748 0 0 0 mysqld kernel: [2963685.664730] Out of memory: Kill process 31716 (mysqld) score 23 or sacrifice child kernel: [2963685.664764] Killed process 31716 (mysqld) total-vm:907784kB, anon-rss:90992kB, file-rss:0kB kernel: [2963686.153608] init: mysql main process (31716) killed by KILL signal kernel: [2963686.169294] init: mysql main process ended, respawning That states that the VM was occupying 0.9GB, but my Ram has 2GB free, so 1GB was still left free. I understand that in Linux applications can allocate more memory than physically available. I don't know if this is the problme, it's the first time that it has started to happen. Obviously, the MySQL server tries to restart, but there's no memory for it apparently and it won't restart. Here is its error log: Plugin 'FEDERATED' is disabled. The InnoDB memory heap is disabled Mutexes and rw_locks use GCC atomic builtins Compressed tables use zlib 1.2.3.4 Initializing buffer pool, size = 128.0M InnoDB: mmap(137363456 bytes) failed; errno 12 Completed initialization of buffer pool Fatal error: cannot allocate memory for the buffer pool Plugin 'InnoDB' init function returned error. Plugin 'InnoDB' registration as a STORAGE ENGINE failed. Unknown/unsupported storage engine: InnoDB [ERROR] Aborting [Note] /usr/sbin/mysqld: Shutdown complete I simply restarted the Mysql service. About two hours later it happened again. I restarted it. Then it happened again 9 hours later. So then I thought of the MaxClients parameter of apache.conf, so I went to check it out. It was set at 150. I decided to drop it down to 60. As so: <IfModule mpm_prefork_module> ... MaxClients 60 </IfModule> <IfModule mpm_worker_module> ... MaxClients 60 </IfModule> <IfModule mpm_event_module> ... MaxClients 60 </IfModule> Once I did that, I had the apache2 service restart and it all went smoothly for 3/4 of a day. Since at night the MySQL service shut down once again, but this time it wasn't killed by the Apache2 service. Instead it called the OOM-Killer with the following message: kernel: [3104680.005312] mysqld invoked oom-killer: gfp_mask=0x201da, order=0, oom_adj=0, oom_score_adj=0 kernel: [3104680.005351] [<ffffffff81119795>] oom_kill_process+0x85/0xb0 kernel: [3104680.548860] init: mysql main process (30821) killed by KILL signal Now I'm out of ideas. Some articles state that the ideal thing to do is change the kernel behaviour with the following (include it to the file /etc/sysctl.conf ) vm.overcommit_memory = 2 vm.overcommit_ratio = 80 So no overcommits will take place. I'm wondering if this is the way to go? Keep in mind I'm no server administrator, I have basic knowldege. Thanks a bunch in advance.

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• How to use iptables to forward all data from an IP to a Virtual Machine

  - by jro

  OK, in an attempt to get some response, a TL;DR version. I know that the following command: iptables -A PREROUTING -t nat -i eth0 --dport 80 --source 1.1.1.1 -j REDIRECT --to-port 8080 ... will redirect all traffic from port 80 to port 8080. The problem is that I have to do this for every port that is to be redirected. To be future-proof, I want all ports for an IP to be redirected to a different (internal) IP, so that if one might decide to enable SSH, they can directly connect without worrying about iptables. What is needed to reliable forward all traffic from an external IP, to an internal IP, and vice versa? Extended version I've scoured the internet for this, but I never got a solid answer. What I have is one physical server (HOST), with several virtual machines (VM) that need traffic redirected to them. Just getting it to work with a single machine is enough for now. The VM's run under VirtualBox, and are set to use a host-only adapter (vboxnet0). Everything seems to work, but it is greatly lagging. Both the host (CentOS 5.6) and the guest (Ubuntu 10.04) machine are running Linux. What I did was the following: Configure the VM to have a static IP in the network of the vboxnet0 adapter. Add an IP alias to the host, registering to the dedicated (outside) IP. Setup iptables to allow traffic to come through (via sysctl). Configure iptables to DNAT and SNAT data from a given IP address to the internal address. iptables commands: sudo iptables -A FORWARD -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT sudo iptables -A POSTROUTING -t nat -j MASQUERADE iptables -t nat -I PREROUTING -d $OUT_IP -I eth0 -j DNAT --to-destination $IN_IP iptables -t nat -I POSTROUTING -s $IN_IP -o eth0 -j SNAT --to-source $OUT_IP Now the site works, but is really, really slow. I'm hoping I missed something simple, but I'm out of ideas for now. Some background info: before this, the site was working with basic port forwarding. E.g. port 80 was mapped to port 8080 using iptables. In VirtualBox (having the network adapter configured as NAT), a port forwarding the other way around made things work beautifully. The problem was twofold: first, multiple ports needed to be forwarded (for admin interfaces, https, ssh, etc). Second, it only allowed one IP address to use port 80. To resolve things, multiple external IP addresses are used for different (sub)domains. Likewise, the "VirtualBox" network will contain the virtual machines: DNS Ext. IP Adapter VM "VirtalBox" IP ------------------------------------------------------------------ a.example.com 1.1.1.1 eth0:1 vm_guest_1 192.168.56.1 b.example.com 2.2.2.2 eth0:2 vm_guest_2 192.168.56.2 c.example.com 3.3.3.3 eth0:3 vm_guest_3 192.168.56.3 And so on. Put simply, the goal is to channel all traffic from a.example.com to vm_guest_1 (of put differently, from 1.1.1.1 to 192.168.56.1). And achieve this with an acceptable speed :).

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• Scan a Windows PC for Viruses from a Ubuntu Live CD

  - by Trevor Bekolay

  Getting a virus is bad. Getting a virus that causes your computer to crash when you reboot is even worse. We’ll show you how to clean viruses from your computer even if you can’t boot into Windows by using a virus scanner in a Ubuntu Live CD. There are a number of virus scanners available for Ubuntu, but we’ve found that avast! is the best choice, with great detection rates and usability. Unfortunately, avast! does not have a proper 64-bit version, and forcing the install does not work properly. If you want to use avast! to scan for viruses, then ensure that you have a 32-bit Ubuntu Live CD. If you currently have a 64-bit Ubuntu Live CD on a bootable flash drive, it does not take long to wipe your flash drive and go through our guide again and select normal (32-bit) Ubuntu 9.10 instead of the x64 edition. For the purposes of fixing your Windows installation, the 64-bit Live CD will not provide any benefits. Once Ubuntu 9.10 boots up, open up Firefox by clicking on its icon in the top panel. Navigate to http://www.avast.com/linux-home-edition. Click on the Download tab, and then click on the link to download the DEB package. Save it to the default location. While avast! is downloading, click on the link to the registration form on the download page. Fill in the registration form if you do not already have a trial license for avast!. By the time you’ve filled out the registration form, avast! will hopefully be finished downloading. Open a terminal window by clicking on Applications in the top-left corner of the screen, then expanding the Accessories menu and clicking on Terminal. In the terminal window, type in the following commands, pressing enter after each line. cd Downloadssudo dpkg –i avast* This will install avast! on the live Ubuntu environment. To ensure that you can use the latest virus database, while still in the terminal window, type in the following command: sudo sysctl –w kernel.shmmax=128000000 Now we’re ready to open avast!. Click on Applications on the top-left corner of the screen, expand the Accessories folder, and click on the new avast! Antivirus item. You will first be greeted with a window that asks for your license key. Hopefully you’ve received it in your email by now; open the email that avast! sends you, copy the license key, and paste it in the Registration window. avast! Antivirus will open. You’ll notice that the virus database is outdated. Click on the Update database button and avast! will start downloading the latest virus database. To scan your Windows hard drive, you will need to “mount” it. While the virus database is downloading, click on Places on the top-left of your screen, and click on your Windows hard drive, if you can tell which one it is by its size. If you can’t tell which is the correct hard drive, then click on Computer and check out each hard drive until you find the right one. When you find it, make a note of the drive’s label, which appears in the menu bar of the file browser. Also note that your hard drive will now appear on your desktop. By now, your virus database should be updated. At the time this article was written, the most recent version was 100404-0. In the main avast! window, click on the radio button next to Selected folders and then click on the “+” button to the right of the list box. It will open up a dialog box to browse to a location. To find your Windows hard drive, click on the “>” next to the computer icon. In the expanded list, find the folder labelled “media” and click on the “>” next to it to expand it. In this list, you should be able to find the label that corresponds to your Windows hard drive. If you want to scan a certain folder, then you can go further into this hierarchy and select that folder. However, we will scan the entire hard drive, so we’ll just press OK. Click on Start scan and avast! will start scanning your hard drive. If a virus is found, you’ll be prompted to select an action. If you know that the file is a virus, then you can Delete it, but there is the possibility of false positives, so you can also choose Move to chest to quarantine it. When avast! is done scanning, it will summarize what it found on your hard drive. You can take different actions on those files at this time by right-clicking on them and selecting the appropriate action. When you’re done, click Close. Your Windows PC is now free of viruses, in the eyes of avast!. Reboot your computer and with any luck it will now boot up! Alternatives to avast! If avast! and a liberal amount of Googling doesn’t fix your problem, it’s possible that a different virus scanner will fix your obscure issue. Here are a list of other virus scanners available for Ubuntu that are either free or offer free trials. See their support forums for help on installing these virus scanners. Avira AntiVir Personal for Linux / Solaris Panda Antivirus for Linux Installation and usage guide from Ubuntu F-PROT Antivirus for Linux ClamAV installation and usage guide from Ubuntu NOD32 Antivirus for Linux Kaspersky Anti-Virus 2010 Bitdefender Antivirus for Unices Conclusion Running avast! from a Ubuntu Live CD can clean the vast majority of viruses from your Windows PC. This is another reason to always have a Ubuntu Live CD ready just in case something happens to your Windows installation! Similar Articles Productive Geek Tips Secure Computing: Windows Live OneCareHow To Remove Antivirus Live and Other Rogue/Fake Antivirus MalwareUse the Windows Key for the "Start" Menu in Ubuntu LinuxScan Files for Viruses Before You Download With Dr.WebAsk the Readers: Share Your Tips for Defeating Viruses and Malware TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 The Ultimate Guide For YouTube Lovers Will it Blend? iPad Edition Penolo Lets You Share Sketches On Twitter Visit Woolyss.com for Old School Games, Music and Videos Add a Custom Title in IE using Spybot or Spyware Blaster When You Need to Hail a Taxi in NYC

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• OpenVPN and PPTP on XEN VPS

  - by amiv

  I have Debian based system (Ubuntu 11.10) on XEN VPS. I've installed OpenVPN and works great. I need to install PPTP too, so did it and clients can connect, but they have no internet on client side. If I connect to VPN over PPTP I can ping and access to only my VPS by its IP, but ony that. There's no "internet" on client side. It looks it's not DNS problems (I'm using 8.8.8.8) because I can't ping known IPs. I bet the solution is simple, but don't have any idea. Any guess? /etc/pptpd.conf option /etc/ppp/pptpd-options logwtmp localip 46.38.xx.xx remoteip 10.1.0.1-10 /etc/ppp/pptpd-options name pptpd refuse-pap refuse-chap refuse-mschap require-mschap-v2 require-mppe-128 ms-dns 8.8.8.8 ms-dns 8.8.4.4 proxyarp nodefaultroute lock nobsdcomp /etc/ppp/ip-up [...] ifconfig ppp0 mtu 1400 /etc/sysctl.conf [...] net.ipv4.ip_forward=1 Command which I run: iptables -t nat -A POSTROUTING -j SNAT --to-source 46.38.xx.xx (IP of my VPS) The client can connect, first one gets IP 10.1.0.1 and DNS from Google. I bet it's iptables problem, am I right? I'm iptables noob and I don't have idea what's wrong. And here's the ifconfig and route command before client connect via PPTP: root@vps3780:~# route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface default xx.xx.tel.ru 0.0.0.0 UG 100 0 0 eth0 10.8.0.0 10.8.0.2 255.255.255.0 UG 0 0 0 tun0 10.8.0.2 * 255.255.255.255 UH 0 0 0 tun0 46.38.xx.0 * 255.255.255.0 U 0 0 0 eth0 root@vps3780:~# ifconfig eth0 Link encap:Ethernet HWaddr 00:16:3e:56:xx:xx inet addr:46.38.xx.xx Bcast:0.0.0.0 Mask:255.255.255.0 inet6 addr: fe80::216:xx:xx:dfb6/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:22671 errors:0 dropped:81 overruns:0 frame:0 TX packets:2266 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:1813358 (1.8 MB) TX bytes:667626 (667.6 KB) Interrupt:24 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:100 errors:0 dropped:0 overruns:0 frame:0 TX packets:100 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:10778 (10.7 KB) TX bytes:10778 (10.7 KB) tun0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 inet addr:10.8.0.1 P-t-P:10.8.0.2 Mask:255.255.255.255 UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1 RX packets:602 errors:0 dropped:0 overruns:0 frame:0 TX packets:612 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:100 RX bytes:90850 (90.8 KB) TX bytes:418904 (418.9 KB) And here's the ifconfig and route command after client connect via PPTP: root@vps3780:~# route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface default xx.xx.tel.ru 0.0.0.0 UG 100 0 0 eth0 10.1.0.1 * 255.255.255.255 UH 0 0 0 ppp0 10.8.0.0 10.8.0.2 255.255.255.0 UG 0 0 0 tun0 10.8.0.2 * 255.255.255.255 UH 0 0 0 tun0 46.38.xx.0 * 255.255.255.0 U 0 0 0 eth0 root@vps3780:~# ifconfig eth0 Link encap:Ethernet HWaddr 00:16:3e:56:xx:xx inet addr:46.38.xx.xx Bcast:0.0.0.0 Mask:255.255.255.0 inet6 addr: fe80::216:xx:xx:dfb6/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:22989 errors:0 dropped:82 overruns:0 frame:0 TX packets:2352 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:1841310 (1.8 MB) TX bytes:678456 (678.4 KB) Interrupt:24 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:112 errors:0 dropped:0 overruns:0 frame:0 TX packets:112 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:12102 (12.1 KB) TX bytes:12102 (12.1 KB) ppp0 Link encap:Point-to-Point Protocol inet addr:46.38.xx.xx P-t-P:10.1.0.1 Mask:255.255.255.255 UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1400 Metric:1 RX packets:66 errors:0 dropped:0 overruns:0 frame:0 TX packets:15 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:3 RX bytes:10028 (10.0 KB) TX bytes:660 (660.0 B) tun0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 inet addr:10.8.0.1 P-t-P:10.8.0.2 Mask:255.255.255.255 UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1 RX packets:602 errors:0 dropped:0 overruns:0 frame:0 TX packets:612 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:100 RX bytes:90850 (90.8 KB) TX bytes:418904 (418.9 KB) And ugly iptables --list output: root@vps3780:~# iptables --list Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy ACCEPT) target prot opt source destination ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED ACCEPT all -- 10.8.0.0/24 anywhere REJECT all -- anywhere anywhere reject-with icmp-port-unreachable ACCEPT all -- 10.1.0.0/24 anywhere ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED ACCEPT all -- 10.1.0.0/24 anywhere REJECT all -- anywhere anywhere reject-with icmp-port-unreachable ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED ACCEPT all -- 10.8.0.0/24 anywhere REJECT all -- anywhere anywhere reject-with icmp-port-unreachable And ugly iptables -t nat -L output: root@vps3780:~# iptables -t nat -L Chain PREROUTING (policy ACCEPT) target prot opt source destination Chain INPUT (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination Chain POSTROUTING (policy ACCEPT) target prot opt source destination SNAT all -- 10.8.0.0/24 anywhere to:46.38.xx.xx MASQUERADE all -- 10.1.0.0/24 anywhere SNAT all -- 10.1.0.0/24 anywhere to:46.38.xx.xx SNAT all -- 10.8.0.0/24 anywhere to:46.38.xx.xx SNAT all -- 10.1.0.0/24 anywhere to:46.38.xx.xx MASQUERADE all -- anywhere anywhere SNAT all -- anywhere anywhere to:46.38.xx.xx SNAT all -- 10.8.0.0/24 anywhere to:46.38.xx.xx MASQUERADE all -- anywhere anywhere MASQUERADE all -- 10.1.0.0/24 anywhere MASQUERADE all -- anywhere anywhere MASQUERADE all -- 10.1.0.0/24 anywhere As I said - OpenVPN works very good. 10.8.0.0/24 for OpenVPN (on tun0). PPTP won't work. 10.1.0.0/24 for PPTP (on ppp0). Clients can connect, but they haven't "internet". Any suggestions will be appreciated. Second whole day fighting with no results. EDIT: iptables -t filter -F - it resolved my problem :-)

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• Help me upgrade my pf.conf for OpenBSD 4.7

  - by polemon

  I'm planning on upgrading my OpenBSD to 4.7 (from 4.6) and as you may or may not know, they changed the syntax for pf.conf. This is the relevant portion from the upgrade guide: pf(4) NAT syntax change As described in more detail in this mailing list post, PF's separate nat/rdr/binat (translation) rules have been replaced with actions on regular match/filter rules. Simple rulesets may be converted like this: nat on $ext_if from 10/8 -> ($ext_if) rdr on $ext_if to ($ext_if) -> 1.2.3.4 becomes match out on $ext_if from 10/8 nat-to ($ext_if) match in on $ext_if to ($ext_if) rdr-to 1.2.3.4 and... binat on $ext_if from $web_serv_int to any -> $web_serv_ext becomes match on $ext_if from $web_serv_int to any binat-to $web_serv_ext nat-anchor and/or rdr-anchor lines, e.g. for relayd(8), ftp-proxy(8) and tftp-proxy(8), are no longer used and should be removed from pf.conf(5), leaving only the anchor lines. Translation rules relating to these and spamd(8) will need to be adjusted as appropriate. N.B.: Previously, translation rules had "stop at first match" behaviour, with binat being evaluated first, followed by nat/rdr depending on direction of the packet. Now the filter rules are subject to the usual "last match" behaviour, so care must be taken with rule ordering when converting. pf(4) route-to/reply-to syntax change The route-to, reply-to, dup-to and fastroute options in pf.conf move to filteropts; pass in on $ext_if route-to (em1 192.168.1.1) from 10.1.1.1 pass in on $ext_if reply-to (em1 192.168.1.1) to 10.1.1.1 becomes pass in on $ext_if from 10.1.1.1 route-to (em1 192.168.1.1) pass in on $ext_if to 10.1.1.1 reply-to (em1 192.168.1.1) Now, this is my current pf.conf: # $OpenBSD: pf.conf,v 1.38 2009/02/23 01:18:36 deraadt Exp $ # # See pf.conf(5) for syntax and examples; this sample ruleset uses # require-order to permit mixing of NAT/RDR and filter rules. # Remember to set net.inet.ip.forwarding=1 and/or net.inet6.ip6.forwarding=1 # in /etc/sysctl.conf if packets are to be forwarded between interfaces. ext_if="pppoe0" int_if="nfe0" int_net="192.168.0.0/24" polemon="192.168.0.10" poletopw="192.168.0.12" segatop="192.168.0.20" table <leechers> persist set loginterface $ext_if set skip on lo match on $ext_if all scrub (no-df max-mss 1440) altq on $ext_if priq bandwidth 950Kb queue {q_pri, q_hi, q_std, q_low} queue q_pri priority 15 queue q_hi priority 10 queue q_std priority 7 priq(default) queue q_low priority 0 nat-anchor "ftp-proxy/*" rdr-anchor "ftp-proxy/*" nat on $ext_if from !($ext_if) -> ($ext_if) rdr pass on $int_if proto tcp to port ftp -> 127.0.0.1 port 8021 rdr pass on $ext_if proto tcp to port 2080 -> $segatop port 80 rdr pass on $ext_if proto tcp to port 2022 -> $segatop port 22 rdr pass on $ext_if proto tcp to port 4000 -> $polemon port 4000 rdr pass on $ext_if proto tcp to port 6600 -> $polemon port 6600 anchor "ftp-proxy/*" block pass on $int_if queue(q_hi, q_pri) pass out on $ext_if queue(q_std, q_pri) pass out on $ext_if proto icmp queue q_pri pass out on $ext_if proto {tcp, udp} to any port ssh queue(q_hi, q_pri) pass out on $ext_if proto {tcp, udp} to any port http queue(q_std, q_pri) #pass out on $ext_if proto {tcp, udp} all queue(q_low, q_hi) pass out on $ext_if proto {tcp, udp} from <leechers> queue(q_low, q_std) pass in on $ext_if proto tcp to ($ext_if) port ident queue(q_hi, q_pri) pass in on $ext_if proto tcp to ($ext_if) port ssh queue(q_hi, q_pri) pass in on $ext_if proto tcp to ($ext_if) port http queue(q_hi, q_pri) pass in on $ext_if inet proto icmp all icmp-type echoreq queue q_pri If someone has experience with porting the 4.6 pf.conf to 4.7, please help me do the correct changes. OK, this is how far I've got: I commented out nat-anchor and rdr-anchor, as describted in the guide: #nat-anchor "ftp-proxy/*" #rdr-anchor "ftp-proxy/*" And this is how I've "converted" the rdr rules: #nat on $ext_if from !($ext_if) -> ($ext_if) match out on $ext_if from !($ext_if) nat-to ($ext_if) #rdr pass on $int_if proto tcp to port ftp -> 127.0.0.1 port 8021 match in on $int_if proto tcp to port ftp rdr-to 127.0.0.1 port 8021 #rdr pass on $ext_if proto tcp to port 2080 -> $segatop port 80 match in on $ext_if proto tcp tp port 2080 rdr-to $segatop port 80 #rdr pass on $ext_if proto tcp to port 2022 -> $segatop port 22 match in on $ext_if proto tcp tp port 2022 rdr-to $segatop port 22 rdr pass on $ext_if proto tcp to port 4000 -> $polemon port 4000 match in on $ext_if proto tcp tp port 4000 rdr-to $polemon port 4000 rdr pass on $ext_if proto tcp to port 6600 -> $polemon port 6600 match in on $ext_if proto tcp tp port 6600 rdr-to $polemon port 6600 Did I miss anything? Is the anchor for ftp-proxy OK as it is now? Do I need to change something in the other pass in on... lines?

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• Nasty mono bug with F#

  - by Aurimas Anskaitis

  Hi, I have this monstrous f# 2.0 program My mono version is Mono JIT compiler version 2.9 (master/f593354 Sun Dec 26 03:15:55 EET 2010) Copyright (C) 2002-2010 Novell, Inc and Contributors. www.mono-project.com TLS: __thread SIGSEGV: altstack Notifications: epoll Architecture: x86 Disabled: none Misc: softdebug LLVM: supported, not enabled. GC: Included Boehm (with typed GC and Parallel Mark) //--------------------------------------------- module Main let rec gcd x y = if y = 0 then x else gcd y (x%y) let main = printfn "%i" (gcd 4 2) main //----------------------------------------------- And the problem is that output from running the program is as follows: Stacktrace: at (wrapper managed-to-native) System.Reflection.MonoMethodInfo.get_parameter_info (intptr,System.Reflection.MemberInfo) <0xffffffff at System.Reflection.MonoMethodInfo.GetParametersInfo (intptr,System.Reflection.MemberInfo) <0x00013 at System.Reflection.MonoCMethod.GetParameters () <0x00015 at System.Reflection.MonoCMethod.Invoke (object,System.Reflection.BindingFlags,System.Reflection.Binder,object[],System.Globalization.CultureInfo) <0x00035 at System.Reflection.MonoCMethod.Invoke (System.Reflection.BindingFlags,System.Reflection.Binder,object[],System.Globalization.CultureInfo) <0x00024 at System.Reflection.ConstructorInfo.Invoke (object[]) <0x0003f at System.Activator.CreateInstance (System.Type,bool) <0x0017c at System.Activator.CreateInstance (System.Type) <0x00012 at Microsoft.FSharp.Reflection.FSharpValue.MakeFunction (System.Type,Microsoft.FSharp.Core.FSharpFunc2<object, object>) <0x00145> at Microsoft.FSharp.Core.PrintfImpl.capture@529<b, c, d> (Microsoft.FSharp.Core.FSharpFunc2, Microsoft.FSharp.Core.FSharpFunc`2<char, Microsoft.FSharp.Core.Unit>, Microsoft.FSharp.Core.FSharpFunc`2,string,int,Microsoft.FSharp.Collections.FSharpList1<object>,System.Type,int) <0x00147> at Microsoft.FSharp.Core.PrintfImpl.gprintf<b, c, d, a> (Microsoft.FSharp.Core.FSharpFunc2, Microsoft.FSharp.Core.FSharpFunc`2<char, Microsoft.FSharp.Core.Unit>, Microsoft.FSharp.Core.FSharpFunc`2,Microsoft.FSharp.Core.PrintfFormat4<a, b, c, d>) <0x000dd> at Microsoft.FSharp.Core.PrintfModule.kprintf_imperative<a, b, c> (Microsoft.FSharp.Core.FSharpFunc2,b,Microsoft.FSharp.Core.FSharpFunc2<char, Microsoft.FSharp.Core.Unit>,Microsoft.FSharp.Core.PrintfFormat4) <0x00058 at Microsoft.FSharp.Core.PrintfModule.PrintFormatToTextWriterThen (Microsoft.FSharp.Core.FSharpFunc2<Microsoft.FSharp.Core.Unit, TResult>,System.IO.TextWriter,Microsoft.FSharp.Core.PrintfFormat4) <0x0004d at Microsoft.FSharp.Core.PrintfModule.PrintFormatLineToTextWriter (System.IO.TextWriter,Microsoft.FSharp.Core.PrintfFormat`4) <0x0004d at .$Main.main@ () <0x00042 Native stacktrace: mono() [0x80dc13b] mono() [0x811c65b] mono() [0x8059a11] [0x7af40c] mono() [0x8228214] mono() [0x8228214] mono() [0x8228214] mono() [0x8228214] mono() [0x8228214] mono() [0x8228214] mono() [0x8228214] mono() [0x8228214] mono() [0x8228282] mono() [0x822991e] mono() [0x822aa9d] mono(mono_array_new_specific+0xea) [0x813ba9a] mono() [0x81c63a1] mono() [0x8149ac8] [0xc04328] [0xc042e4] [0xc042be] [0xc0455e] [0xc0451d] [0xc044d8] [0xc0349d] [0xc0330b] [0xc02f9e] [0xbfe960] [0xbfe6c6] [0xbfe571] [0xbfe4de] [0xbfe44e] [0xbf9d2b] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] 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[0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] [0x9bf0724] Debug info from gdb: Could not attach to process. If your uid matches the uid of the target process, check the setting of /proc/sys/kernel/yama/ptrace_scope, or try again as the root user. For more details, see /etc/sysctl.d/10-ptrace.conf ptrace: Operation not permitted. ================================================================= Got a SIGSEGV while executing native code. This usually indicates a fatal error in the mono runtime or one of the native libraries used by your application. Aborted It is a huge problem with mono or f#? By the way, the same function works when using pattern matching instead of "if".

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• CentOS Client - Unable to Establish iSCSI connection with multiple interfaces on the initiator

  - by slashdot

  So after upgrading to CentOS 6.2, I am seemingly no longer able to login into my iSCSI targets. I have multiple interfaces on different subnets on the system, and I first thought that it had to do with the fact that I may not be binding correct interfaces, which seems to be the case when looking at netstat, as this is clearly wrong: [root]? netstat -na|grep .90 tcp 0 1 10.10.100.60:42354 10.10.8.90:3260 SYN_SENT tcp 0 1 10.10.100.60:40777 10.10.9.90:3260 SYN_SENT I then went ahead and disabled all but one interface, and so as a result netstat appears to be correct, but the issue with login remains. I am positive that the target never sees a packet, because I see nothing by SYN_SENT. I know the problem is on my client, because the target is servicing multiple systems, none of which are CentOS 6.2. At this point I am pretty confident that some things changed between CentOS 6.0/6.1 and 6.2. So, if anyone have any thoughts, or ran into this, I would very much like to hear your thoughts. [root]? iscsiadm --mode node --targetname iqn.2011-12.dom.homer:01:lab-centos-servers-00001 --portal 10.10.8.90:3260,2 --interface=sw-iscsi-0 --login Logging in to [iface: sw-iscsi-0, target: iqn.2011-12.dom.homer:01:lab-centos-servers-00001, portal: 10.10.8.90,3260] (multiple) iscsiadm: Could not login to [iface: sw-iscsi-0, target: iqn.2011-12.dom.homer:01:lab-centos-servers-00001, portal: 10.10.8.90,3260]. iscsiadm: initiator reported error (8 - connection timed out) iscsiadm: Could not log into all portals [root]? netstat -rn Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface 10.10.8.0 0.0.0.0 255.255.255.0 U 0 0 0 eth2.7 10.10.9.0 0.0.0.0 255.255.255.0 U 0 0 0 eth3.7 10.10.100.0 0.0.0.0 255.255.252.0 U 0 0 0 eth0 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth1 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth2 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth3 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth2.7 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth3.7 0.0.0.0 10.10.100.1 0.0.0.0 UG 0 0 0 eth0 Output of ip addr show for the two interfaces involved: [root]? for i in 2.7 3.7; do ip addr show eth$i; done 6: eth2.7@eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP link/ether 00:0c:29:94:5b:8d brd ff:ff:ff:ff:ff:ff inet 10.10.8.60/24 brd 10.10.8.255 scope global eth2.7 inet6 fe80::20c:29ff:fe94:5b8d/64 scope link valid_lft forever preferred_lft forever 7: eth3.7@eth3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP link/ether 00:0c:29:94:5b:97 brd ff:ff:ff:ff:ff:ff inet 10.10.9.60/24 brd 10.10.9.255 scope global eth3.7 inet6 fe80::20c:29ff:fe94:5b97/64 scope link valid_lft forever preferred_lft forever Update 01/06/2012: This issue is getting even more interesting by the day it seems. I went a few weeks back and grabbed a snapshot of this system from before upgrading to 6.2. I spun up a new system from the snapshot, and reconfigured interface info and host keys, as well as iSCSI initiator and iscsi interface info to match new MACs. Changed nothing else. Then, I attempted to connect to my targets, and no issues at all. I cannot say that this was unexpected. I then went ahead and compared sysctl settings from both systems and there were differences after the upgrade, but nothing seemingly relevant to iSCSI or IP that could contribute to this. I also noticed that by default now two sessions per connection were enabled after the upgrade, but I changed it back to 1 session in /etc/iscsi/iscsid.conf. On the problematic system we can see that source interface is seemingly wrong, but even when I disable the 10.10.100 interface, problems persist. So, while this may be relevant, I could not validate it for certain. Needless to say, further research is necessary. Something is clearly different between releases. Working system is on 6.1, and non-working is 6.2. ::Working System:: tcp 0 0 10.10.8.210:39566 10.10.8.90:3260 ESTABLISHED tcp 0 0 10.10.9.210:46518 10.10.9.90:3260 ESTABLISHED [root]? ip route show 10.10.8.0/24 dev eth2.6 proto kernel scope link src 10.10.8.210 10.10.9.0/24 dev eth3.7 proto kernel scope link src 10.10.9.210 10.10.100.0/22 dev eth0 proto kernel scope link src 10.10.100.210 169.254.0.0/16 dev eth0 scope link metric 1002 169.254.0.0/16 dev eth2.6 scope link metric 1006 169.254.0.0/16 dev eth3.7 scope link metric 1007 default via 10.10.100.1 dev eth0 ::Non-working System:: tcp 0 1 10.10.100.60:44737 10.10.9.90:3260 SYN_SENT tcp 0 1 10.10.100.60:55479 10.10.8.90:3260 SYN_SENT [root]? ip route show 10.10.8.0/24 dev eth2.6 proto kernel scope link src 10.10.8.60 10.10.9.0/24 dev eth3.7 proto kernel scope link src 10.10.9.60 10.10.100.0/22 dev eth0 proto kernel scope link src 10.10.100.60 169.254.0.0/16 dev eth0 scope link metric 1002 169.254.0.0/16 dev eth2.6 scope link metric 1006 169.254.0.0/16 dev eth3.7 scope link metric 1007 default via 10.10.100.1 dev eth0 And the result is still same: [root]? iscsiadm: Could not login to [iface: sw-iscsi-0, target: iqn.2011-12.dom.homer:01:lab-centos-servers-00001, portal: 10.10.8.90,3260]. iscsiadm: initiator reported error (8 - connection timed out) iscsiadm: Could not login to [iface: sw-iscsi-1, target: iqn.2011-12.dom.homer:02:lab-centos-servers-00001, portal: 10.10.9.90,3260]. iscsiadm: initiator reported error (8 - connection timed out) iscsiadm: Could not log into all portals Update 01/08/2012: I believe I have been able to figure out the answer to my issue. It is quite obscure and I doubt this will happen to anyone else any time soon. It turns out that setting iface.iscsi_ifacename and iface.hwaddress in the interfaces configuration file is not legal. When one manually adds an iscsi target, such as below, all settings from the interface config file are copied into the node config file, that gets created by the below command. Result is parameters iface.iscsi_ifacename and iface.hwaddress together in the same config file. These parameters are seemingly mutually exclusive, which does not exactly make sense, or there is perhaps an oversight in the codepath. Perhaps I will investigate further. # iscsiadm -m node --op new -T iqn.2011-12.dom.homer:01:lab-centos-servers-00001 -p 10.10.8.90,3260,2 -I sw-iscsi-0 # iscsiadm -m node --op new -T iqn.2011-12.dom.homer:02:lab-centos-servers-00001 -p 10.10.9.90,3260,2 -I sw-iscsi-1 Notice, below I commented out iface.hwaddress and iface.ipaddress, after which I re-added targets, with same command as above. All works just fine. [root]? cat * # BEGIN RECORD 2.0-872.33.el6 iface.iscsi_ifacename = sw-iscsi-0 iface.net_ifacename = eth2.6 #iface.hwaddress = XX:XX:XX:XX:XX:XX #iface.ipaddress = 10.10.8.60 iface.transport_name = tcp iface.vlan_id = 6 iface.vlan_priority = 0 iface.iface_num = 0 iface.mtu = 0 iface.port = 0 # END RECORD # BEGIN RECORD 2.0-872.33.el6 iface.iscsi_ifacename = sw-iscsi-1 iface.net_ifacename = eth3.7 #iface.hwaddress = XX:XX:XX:XX:XX:XX #iface.ipaddress = 10.10.9.60 iface.transport_name = tcp iface.vlan_id = 7 iface.vlan_priority = 0 iface.iface_num = 0 iface.mtu = 0 iface.port = 0 # END RECORD Again, chances of this happening to someone else are slim to none, so likely waste of time typing this up. But, if someone does encounter this issue, I hope this post will help.

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• Stop duplicate icmp echo replies when bridging to a dummy interface?

  - by mbrownnyc

  I recently configured a bridge br0 with members as eth0 (real if) and dummy0 (dummy.ko if). When I ping this machine, I receive duplicate replies as: # ping SERVERA PING SERVERA.domain.local (192.168.100.115) 56(84) bytes of data. 64 bytes from SERVERA.domain.local (192.168.100.115): icmp_seq=1 ttl=62 time=113 ms 64 bytes from SERVERA.domain.local (192.168.100.115): icmp_seq=1 ttl=62 time=114 ms (DUP!) 64 bytes from SERVERA.domain.local (192.168.100.115): icmp_seq=2 ttl=62 time=113 ms 64 bytes from SERVERA.domain.local (192.168.100.115): icmp_seq=2 ttl=62 time=113 ms (DUP!) Using tcpdump on SERVERA, I was able to see icmp echo replies being sent from eth0 and br0 itself as follows (oddly two echo request packets arrive "from" my Windows box myhost): 23:19:05.324192 IP myhost.domain.local > SERVERA.domain.local: ICMP echo request, id 512, seq 43781, length 40 23:19:05.324212 IP SERVERA.domain.local > myhost.domain.local: ICMP echo reply, id 512, seq 43781, length 40 23:19:05.324217 IP myhost.domain.local > SERVERA.domain.local: ICMP echo request, id 512, seq 43781, length 40 23:19:05.324221 IP SERVERA.domain.local > myhost.domain.local: ICMP echo reply, id 512, seq 43781, length 40 23:19:05.324264 IP SERVERA.domain.local > myhost.domain.local: ICMP echo reply, id 512, seq 43781, length 40 23:19:05.324272 IP SERVERA.domain.local > myhost.domain.local: ICMP echo reply, id 512, seq 43781, length 40 It's worth noting, testing reveals that hosts on the same physical switch do not see DUP icmp echo responses (a host on the same VLAN on another switch does see a dup icmp echo response). I've read that this could be due to the ARP table of a switch, but I can't find any info directly related to bridges, just bonds. I have a feeling my problem lay in the stack on linux, not the switch, but am opened to any suggestions. The system is running centos6/el6 kernel 2.6.32-71.29.1.el6.i686. How do I stop ICMP echo replies from being sent in duplicate when dealing with a bridge interface/bridged interfaces? Thanks, Matt [edit] Quick note: It was recommended in #linux to: [08:53] == mbrownnyc [gateway/web/freenode/] has joined ##linux [08:57] <lkeijser> mbrownnyc: what happens if you set arp_ignore to 1 for the dummy interface? [08:59] <lkeijser> also set arp_announce to 2 for that interface [09:24] <mbrownnyc> lkeijser: I set arp_annouce to 2, arp_ignore to 2 in /etc/sysctl.conf and rebooted the machine... verifying that the bits are set after boot... the problem is still present I did this and came up empty. Same dup problem. I will be moving away from including the dummy interface in the bridge as: [09:31] == mbrownnyc [gateway/web/freenode/] has joined #Netfilter [09:31] <mbrownnyc> Hello all... I'm wondering, is it correct that even with an interface in PROMISC that the kernel will drop /some/ packets before they reach applications? [09:31] <whaffle> What would you make think so? [09:32] <mbrownnyc> I ask because I am receiving ICMP echo replies after configuring a bridge with a dummy interface in order for ipt_netflow to see all packets, only as reported in it's documentation: http://ipt-netflow.git.sourceforge.net/git/gitweb.cgi?p=ipt-netflow/ipt-netflow;a=blob;f=README.promisc [09:32] <mbrownnyc> but I do not know if PROMISC will do the same job [09:33] <mbrownnyc> I was referred here from #linux. any assistance is appreciated [09:33] <whaffle> The following conditions need to be met: PROMISC is enabled (bridges and applications like tcpdump will do this automatically, otherwise they won't function). [09:34] <whaffle> If an interface is part of a bridge, then all packets that enter the bridge should already be visible in the raw table. [09:35] <mbrownnyc> thanks whaffle PROMISC must be set manually for ipt_netflow to function, but [09:36] <whaffle> promisc does not need to be set manually, because the bridge will do it for you. [09:36] <whaffle> When you do not have a bridge, you can easily create one, thereby rendering any kernel patches moot. [09:36] <mbrownnyc> whaffle: I speak without the bridge [09:36] <whaffle> It is perfectly valid to have a "half-bridge" with only a single interface in it. [09:36] <mbrownnyc> whaffle: I am unfamiliar with the raw table, does this mean that PROMISC allows the raw table to be populated with packets the same as if the interface was part of a bridge? [09:37] <whaffle> Promisc mode will cause packets with {a dst MAC address that does not equal the interface's MAC address} to be delivered from the NIC into the kernel nevertheless. [09:37] <mbrownnyc> whaffle: I suppose I mean to clearly ask: what benefit would creating a bridge have over setting an interface PROMISC? [09:38] <mbrownnyc> whaffle: from your last answer I feel that the answer to my question is "none," is this correct? [09:39] <whaffle> Furthermore, the linux kernel itself has a check for {packets with a non-local MAC address}, so that packets that will not enter a bridge will be discarded as well, even in the face of PROMISC. [09:46] <mbrownnyc> whaffle: so, this last bit of information is quite clearly why I would need and want a bridge in my situation [09:46] <mbrownnyc> okay, the ICMP echo reply duplicate issue is likely out of the realm of this channel, but I sincerely appreciate the info on the kernels inner-workings [09:52] <whaffle> mbrownnyc: either the kernel patch, or a bridge with an interface. Since the latter is quicker, yes [09:54] <mbrownnyc> thanks whaffle [edit2] After removing the bridge, and removing the dummy kernel module, I only had a single interface chilling out, lonely. I still received duplicate icmp echo replies... in fact I received a random amount: http://pastebin.com/2LNs0GM8 The same thing doesn't happen on a few other hosts on the same switch, so it has to do with the linux box itself. I'll likely end up rebuilding it next week. Then... you know... this same thing will occur again. [edit3] Guess what? I rebuilt the box, and I'm still receiving duplicate ICMP echo replies. Must be the network infrastructure, although the ARP tables do not contain multiple entries. [edit4] How ridiculous. The machine was a network probe, so I was (ingress and egress) mirroring an uplink port to a node that was the NIC. So, the flow (must have) gone like this: ICMP echo request comes in through the mirrored uplink port. (the real) ICMP echo request is received by the NIC (the mirrored) ICMP echo request is received by the NIC ICMP echo reply is sent for both. I'm ashamed of myself, but now I know. It was suggested on #networking to either isolate the mirrored traffic to an interface that does not have IP enabled, or tag the mirrored packets with dot1q.

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• Does my basic PHP Socket Server need optimization?

  - by Tom

  Like many people, I can do a lot of things with PHP. One problem I do face constantly is that other people can do it much cleaner, much more organized and much more structured. This also results in much faster execution times and much less bugs. I just finished writing a basic PHP Socket Server (the real core), and am asking you if you can tell me what I should do different before I start expanding the core. I'm not asking about improvements such as encrypted data, authentication or multi-threading. I'm more wondering about questions like "should I maybe do it in a more object oriented way (using PHP5)?", or "is the general structure of the way the script works good, or should some things be done different?". Basically, "is this how the core of a socket server should work?" In fact, I think that if I just show you the code here many of you will immediately see room for improvements. Please be so kind to tell me. Thanks! #!/usr/bin/php -q <? // config $timelimit = 180; // amount of seconds the server should run for, 0 = run indefintely $address = $_SERVER['SERVER_ADDR']; // the server's external IP $port = 9000; // the port to listen on $backlog = SOMAXCONN; // the maximum of backlog incoming connections that will be queued for processing // configure custom PHP settings error_reporting(1); // report all errors ini_set('display_errors', 1); // display all errors set_time_limit($timelimit); // timeout after x seconds ob_implicit_flush(); // results in a flush operation after every output call //create master IPv4 based TCP socket if (!($master = socket_create(AF_INET, SOCK_STREAM, SOL_TCP))) die("Could not create master socket, error: ".socket_strerror(socket_last_error())); // set socket options (local addresses can be reused) if (!socket_set_option($master, SOL_SOCKET, SO_REUSEADDR, 1)) die("Could not set socket options, error: ".socket_strerror(socket_last_error())); // bind to socket server if (!socket_bind($master, $address, $port)) die("Could not bind to socket server, error: ".socket_strerror(socket_last_error())); // start listening if (!socket_listen($master, $backlog)) die("Could not start listening to socket, error: ".socket_strerror(socket_last_error())); //display startup information echo "[".date('Y-m-d H:i:s')."] SERVER CREATED (MAXCONN: ".SOMAXCONN.").\n"; //max connections is a kernel variable and can be adjusted with sysctl echo "[".date('Y-m-d H:i:s')."] Listening on ".$address.":".$port.".\n"; $time = time(); //set startup timestamp // init read sockets array $read_sockets = array($master); // continuously handle incoming socket messages, or close if time limit has been reached while ((!$timelimit) or (time() - $time < $timelimit)) { $changed_sockets = $read_sockets; socket_select($changed_sockets, $write = null, $except = null, null); foreach($changed_sockets as $socket) { if ($socket == $master) { if (($client = socket_accept($master)) < 0) { echo "[".date('Y-m-d H:i:s')."] Socket_accept() failed, error: ".socket_strerror(socket_last_error())."\n"; continue; } else { array_push($read_sockets, $client); echo "[".date('Y-m-d H:i:s')."] Client #".count($read_sockets)." connected (connections: ".count($read_sockets)."/".SOMAXCONN.")\n"; } } else { $data = @socket_read($socket, 1024, PHP_NORMAL_READ); //read a maximum of 1024 bytes until a new line has been sent if ($data === false) { //the client disconnected $index = array_search($socket, $read_sockets); unset($read_sockets[$index]); socket_close($socket); echo "[".date('Y-m-d H:i:s')."] Client #".($index-1)." disconnected (connections: ".count($read_sockets)."/".SOMAXCONN.")\n"; } else { if ($data = trim($data)) { //remove whitespace and continue only if the message is not empty switch ($data) { case "exit": //close connection when exit command is given $index = array_search($socket, $read_sockets); unset($read_sockets[$index]); socket_close($socket); echo "[".date('Y-m-d H:i:s')."] Client #".($index-1)." disconnected (connections: ".count($read_sockets)."/".SOMAXCONN.")\n"; break; default: //for experimental purposes, write the given data back socket_write($socket, "\n you wrote: ".$data); } } } } } } socket_close($master); //close the socket echo "[".date('Y-m-d H:i:s')."] SERVER CLOSED.\n"; ?>

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• FreeBSD 8.1 unstable network connection

  - by frankcheong

  I have three FreeBSD 8.1 running on three different hardware and therefore consist of different network adapter as well (bce, bge and igb). I found that the network connection is kind of unstable which I have tried to scp some 10MB file and found that I cannot always get the files completed successfully. I have further checked with my network admin and he claim that the problem is being caused by the network driver which cannot support the load whereby he tried to ping using huge packet size (around 15k) and my server will drop packet consistently at a regular interval. I found that this statement may not be valid since the three server is using three different network drive and it would be quite impossible that the same problem is being caused by three different network adapter and thus different network driver. Since then I have tried to tune up the performance by playing around with the /etc/sysctl.conf figures with no luck. kern.ipc.somaxconn=1024 kern.ipc.shmall=3276800 kern.ipc.shmmax=1638400000 # Security net.inet.ip.redirect=0 net.inet.ip.sourceroute=0 net.inet.ip.accept_sourceroute=0 net.inet.icmp.maskrepl=0 net.inet.icmp.log_redirect=0 net.inet.icmp.drop_redirect=1 net.inet.tcp.drop_synfin=1 # Security net.inet.udp.blackhole=1 net.inet.tcp.blackhole=2 # Required by pf net.inet.ip.forwarding=1 #Network Performance Tuning kern.ipc.maxsockbuf=16777216 net.inet.tcp.rfc1323=1 net.inet.tcp.sendbuf_max=16777216 net.inet.tcp.recvbuf_max=16777216 # Setting specifically for 1 or even 10Gbps network net.local.stream.sendspace=262144 net.local.stream.recvspace=262144 net.inet.tcp.local_slowstart_flightsize=10 net.inet.tcp.nolocaltimewait=1 net.inet.tcp.mssdflt=1460 net.inet.tcp.sendbuf_auto=1 net.inet.tcp.sendbuf_inc=16384 net.inet.tcp.recvbuf_auto=1 net.inet.tcp.recvbuf_inc=524288 net.inet.tcp.sendspace=262144 net.inet.tcp.recvspace=262144 net.inet.udp.recvspace=262144 kern.ipc.maxsockbuf=16777216 kern.ipc.nmbclusters=32768 net.inet.tcp.delayed_ack=1 net.inet.tcp.delacktime=100 net.inet.tcp.slowstart_flightsize=179 net.inet.tcp.inflight.enable=1 net.inet.tcp.inflight.min=6144 # Reduce the cache size of slow start connection net.inet.tcp.hostcache.expire=1 Our network admin also claim that they see quite a lot of network up and down from their cisco switch log while I cannot find any up down message inside the dmesg. Have further checked the netstat -s but dont have concrete idea. tcp: 133695291 packets sent 39408539 data packets (3358837321 bytes) 61868 data packets (89472844 bytes) retransmitted 24 data packets unnecessarily retransmitted 0 resends initiated by MTU discovery 50756141 ack-only packets (2148 delayed) 0 URG only packets 0 window probe packets 4372385 window update packets 39781869 control packets 134898031 packets received 72339403 acks (for 3357601899 bytes) 190712 duplicate acks 0 acks for unsent data 59339201 packets (3647021974 bytes) received in-sequence 114 completely duplicate packets (135202 bytes) 27 old duplicate packets 0 packets with some dup. data (0 bytes duped) 42090 out-of-order packets (60817889 bytes) 0 packets (0 bytes) of data after window 0 window probes 3953896 window update packets 64181 packets received after close 0 discarded for bad checksums 0 discarded for bad header offset fields 0 discarded because packet too short 45192 discarded due to memory problems 19945391 connection requests 1323420 connection accepts 0 bad connection attempts 0 listen queue overflows 0 ignored RSTs in the windows 21133581 connections established (including accepts) 21268724 connections closed (including 32737 drops) 207874 connections updated cached RTT on close 207874 connections updated cached RTT variance on close 132439 connections updated cached ssthresh on close 42392 embryonic connections dropped 72339338 segments updated rtt (of 69477829 attempts) 390871 retransmit timeouts 0 connections dropped by rexmit timeout 0 persist timeouts 0 connections dropped by persist timeout 0 Connections (fin_wait_2) dropped because of timeout 13990 keepalive timeouts 2 keepalive probes sent 13988 connections dropped by keepalive 173044 correct ACK header predictions 36947371 correct data packet header predictions 1323420 syncache entries added 0 retransmitted 0 dupsyn 0 dropped 1323420 completed 0 bucket overflow 0 cache overflow 0 reset 0 stale 0 aborted 0 badack 0 unreach 0 zone failures 1323420 cookies sent 0 cookies received 1864 SACK recovery episodes 18005 segment rexmits in SACK recovery episodes 26066896 byte rexmits in SACK recovery episodes 147327 SACK options (SACK blocks) received 87473 SACK options (SACK blocks) sent 0 SACK scoreboard overflow 0 packets with ECN CE bit set 0 packets with ECN ECT(0) bit set 0 packets with ECN ECT(1) bit set 0 successful ECN handshakes 0 times ECN reduced the congestion window udp: 5141258 datagrams received 0 with incomplete header 0 with bad data length field 0 with bad checksum 1 with no checksum 0 dropped due to no socket 129616 broadcast/multicast datagrams undelivered 0 dropped due to full socket buffers 0 not for hashed pcb 5011642 delivered 5016050 datagrams output 0 times multicast source filter matched sctp: 0 input packets 0 datagrams 0 packets that had data 0 input SACK chunks 0 input DATA chunks 0 duplicate DATA chunks 0 input HB chunks 0 HB-ACK chunks 0 input ECNE chunks 0 input AUTH chunks 0 chunks missing AUTH 0 invalid HMAC ids received 0 invalid secret ids received 0 auth failed 0 fast path receives all one chunk 0 fast path multi-part data 0 output packets 0 output SACKs 0 output DATA chunks 0 retransmitted DATA chunks 0 fast retransmitted DATA chunks 0 FR's that happened more than once to same chunk 0 intput HB chunks 0 output ECNE chunks 0 output AUTH chunks 0 ip_output error counter Packet drop statistics: 0 from middle box 0 from end host 0 with data 0 non-data, non-endhost 0 non-endhost, bandwidth rep only 0 not enough for chunk header 0 not enough data to confirm 0 where process_chunk_drop said break 0 failed to find TSN 0 attempt reverse TSN lookup 0 e-host confirms zero-rwnd 0 midbox confirms no space 0 data did not match TSN 0 TSN's marked for Fast Retran Timeouts: 0 iterator timers fired 0 T3 data time outs 0 window probe (T3) timers fired 0 INIT timers fired 0 sack timers fired 0 shutdown timers fired 0 heartbeat timers fired 0 a cookie timeout fired 0 an endpoint changed its cookiesecret 0 PMTU timers fired 0 shutdown ack timers fired 0 shutdown guard timers fired 0 stream reset timers fired 0 early FR timers fired 0 an asconf timer fired 0 auto close timer fired 0 asoc free timers expired 0 inp free timers expired 0 packet shorter than header 0 checksum error 0 no endpoint for port 0 bad v-tag 0 bad SID 0 no memory 0 number of multiple FR in a RTT window 0 RFC813 allowed sending 0 RFC813 does not allow sending 0 times max burst prohibited sending 0 look ahead tells us no memory in interface 0 numbers of window probes sent 0 times an output error to clamp down on next user send 0 times sctp_senderrors were caused from a user 0 number of in data drops due to chunk limit reached 0 number of in data drops due to rwnd limit reached 0 times a ECN reduced the cwnd 0 used express lookup via vtag 0 collision in express lookup 0 times the sender ran dry of user data on primary 0 same for above 0 sacks the slow way 0 window update only sacks sent 0 sends with sinfo_flags !=0 0 unordered sends 0 sends with EOF flag set 0 sends with ABORT flag set 0 times protocol drain called 0 times we did a protocol drain 0 times recv was called with peek 0 cached chunks used 0 cached stream oq's used 0 unread messages abandonded by close 0 send burst avoidance, already max burst inflight to net 0 send cwnd full avoidance, already max burst inflight to net 0 number of map array over-runs via fwd-tsn's ip: 137814085 total packets received 0 bad header checksums 0 with size smaller than minimum 0 with data size < data length 0 with ip length > max ip packet size 0 with header length < data size 0 with data length < header length 0 with bad options 0 with incorrect version number 1200 fragments received 0 fragments dropped (dup or out of space) 0 fragments dropped after timeout 300 packets reassembled ok 137813009 packets for this host 530 packets for unknown/unsupported protocol 0 packets forwarded (0 packets fast forwarded) 61 packets not forwardable 0 packets received for unknown multicast group 0 redirects sent 137234598 packets sent from this host 0 packets sent with fabricated ip header 685307 output packets dropped due to no bufs, etc. 52 output packets discarded due to no route 300 output datagrams fragmented 1200 fragments created 0 datagrams that can't be fragmented 0 tunneling packets that can't find gif 0 datagrams with bad address in header icmp: 0 calls to icmp_error 0 errors not generated in response to an icmp message Output histogram: echo reply: 305 0 messages with bad code fields 0 messages less than the minimum length 0 messages with bad checksum 0 messages with bad length 0 multicast echo requests ignored 0 multicast timestamp requests ignored Input histogram: destination unreachable: 530 echo: 305 305 message responses generated 0 invalid return addresses 0 no return routes ICMP address mask responses are disabled igmp: 0 messages received 0 messages received with too few bytes 0 messages received with wrong TTL 0 messages received with bad checksum 0 V1/V2 membership queries received 0 V3 membership queries received 0 membership queries received with invalid field(s) 0 general queries received 0 group queries received 0 group-source queries received 0 group-source queries dropped 0 membership reports received 0 membership reports received with invalid field(s) 0 membership reports received for groups to which we belong 0 V3 reports received without Router Alert 0 membership reports sent arp: 376748 ARP requests sent 3207 ARP replies sent 245245 ARP requests received 80845 ARP replies received 326090 ARP packets received 267712 total packets dropped due to no ARP entry 108876 ARP entrys timed out 0 Duplicate IPs seen ip6: 2226633 total packets received 0 with size smaller than minimum 0 with data size < data length 0 with bad options 0 with incorrect version number 0 fragments received 0 fragments dropped (dup or out of space) 0 fragments dropped after timeout 0 fragments that exceeded limit 0 packets reassembled ok 2226633 packets for this host 0 packets forwarded 0 packets not forwardable 0 redirects sent 2226633 packets sent from this host 0 packets sent with fabricated ip header 0 output packets dropped due to no bufs, etc. 8 output packets discarded due to no route 0 output datagrams fragmented 0 fragments created 0 datagrams that can't be fragmented 0 packets that violated scope rules 0 multicast packets which we don't join Input histogram: UDP: 2226633 Mbuf statistics: 962679 one mbuf 1263954 one ext mbuf 0 two or more ext mbuf 0 packets whose headers are not continuous 0 tunneling packets that can't find gif 0 packets discarded because of too many headers 0 failures of source address selection Source addresses selection rule applied: icmp6: 0 calls to icmp6_error 0 errors not generated in response to an icmp6 message 0 errors not generated because of rate limitation 0 messages with bad code fields 0 messages < minimum length 0 bad checksums 0 messages with bad length Histogram of error messages to be generated: 0 no route 0 administratively prohibited 0 beyond scope 0 address unreachable 0 port unreachable 0 packet too big 0 time exceed transit 0 time exceed reassembly 0 erroneous header field 0 unrecognized next header 0 unrecognized option 0 redirect 0 unknown 0 message responses generated 0 messages with too many ND options 0 messages with bad ND options 0 bad neighbor solicitation messages 0 bad neighbor advertisement messages 0 bad router solicitation messages 0 bad router advertisement messages 0 bad redirect messages 0 path MTU changes rip6: 0 messages received 0 checksum calculations on inbound 0 messages with bad checksum 0 messages dropped due to no socket 0 multicast messages dropped due to no socket 0 messages dropped due to full socket buffers 0 delivered 0 datagrams output netstat -m 516/5124/5640 mbufs in use (current/cache/total) 512/1634/2146/32768 mbuf clusters in use (current/cache/total/max) 512/1536 mbuf+clusters out of packet secondary zone in use (current/cache) 0/1303/1303/12800 4k (page size) jumbo clusters in use (current/cache/total/max) 0/0/0/6400 9k jumbo clusters in use (current/cache/total/max) 0/0/0/3200 16k jumbo clusters in use (current/cache/total/max) 1153K/9761K/10914K bytes allocated to network (current/cache/total) 0/0/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters) 0/0/0 requests for jumbo clusters denied (4k/9k/16k) 0/8/6656 sfbufs in use (current/peak/max) 0 requests for sfbufs denied 0 requests for sfbufs delayed 0 requests for I/O initiated by sendfile 0 calls to protocol drain routines Anyone got an idea what might be the possible cause?

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