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  • How can I setup a Proxy I can sniff traffic from using an ESX vswitch in promiscuous mode?

    - by sandroid
    I have a pretty specific requirement, detailed below. Here's what I'm not looking for help for, to keep things tidy and on topic: How to configure a standard proxy Any ESX setup required to facilitate traffic sniffing How to sniff traffic Any changes in design (my scope limits me) I need to setup a test environment for a network-sniffing based HTTP app monitoring tool, and I need to troubleshoot a client issue but he only has a prod network, so making changes to the config on client's system "just to try" is costly. The goal here is to create a similar system in my lab, and hit the client's webapp and redirect my traffic - using a proxy - into the lab environment. The reason I want to use a proxy is so that only this specific traffic is redirected for all to see, and not all my web traffic (like my visits to serverfault :P). Everything will run inside an ESX 4.1 machine. In there, there is a traffic collection vswitch in promiscuous mode that is not on the local network for security reasons. The VM containing our listening agent is connected to this vswitch. On the same ESX host, I will setup a basic linux server and install a proxy (either apache + mod_proxy or squid, doesn't matter). I'm looking for ideas on how to deploy this for my needs so I can then figure out how to set it up accordingly. Some ideas I've had were to setup two proxies, and have them talk to eachother through this vswitch in promiscuous mode, but it seems like alot of work. Another idea is a dual-homed proxy, but I've never seen/done that before so I'm not sure how doable it is for what I'd like. I am OK with setting up a second vswitch in promiscuous mode to facilitate this if need be, but I cannot put the vswitch on the lan (which is used so my browser would communicate with the proxy) in promiscuous mode. Any ideas are welcome.

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  • big cpu load on vmware server / linux

    - by dezfafara
    Hi, I currently using a server 2.x hosting 4 virtual machines on a linux system Today, on my physical server, I saw an enormous load average: this is the "top" of the server, illustrating my 4 virtual guests. top - 11:02:02 up 194 days, 23:09, 5 users, load average: 18.78, 12.05, 13.55 Tasks: 113 total, 4 running, 109 sleeping, 0 stopped, 0 zombie Cpu0 : 71.6%us, 19.0%sy, 0.0%ni, 8.8%id, 0.0%wa, 0.3%hi, 0.3%si, 0.0%st Cpu1 : 74.3%us, 10.4%sy, 0.0%ni, 15.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu2 : 72.5%us, 17.6%sy, 0.0%ni, 9.8%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu3 : 79.5%us, 4.6%sy, 0.0%ni, 16.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 8178884k total, 8129980k used, 48904k free, 134904k buffers Swap: 10490436k total, 148k used, 10490288k free, 6129728k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 7312 root 6 -10 1149m 921m 559m R 97 11.5 107947:09 vmware-vmx 6995 root 6 -10 779m 687m 317m R 92 8.6 107374:31 vmware-vmx 6693 root 6 -10 880m 659m 409m S 85 8.3 76947:33 vmware-vmx 12937 root 6 -10 960m 719m 523m S 75 9.0 67219:49 vmware-vmx In bold are the cpu usage for my 4 virtuals guests These guests are running on a linux system, and the appropriate process are usually 5% - 15% of cpu I don't understang why , since a few days I have this big problem. This is the "top" on a virtual guest which is at 95% of cpu load top - 11:23:15 up 194 days, 23:13, 4 users, load average: 0.25, 0.47, 0.59 Tasks: 92 total, 2 running, 90 sleeping, 0 stopped, 0 zombie Cpu(s): 1.4%us, 7.7%sy, 0.0%ni, 90.5%id, 0.5%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 382296k total, 369732k used, 12564k free, 145156k buffers Swap: 979924k total, 13956k used, 965968k free, 86988k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 3691 root 20 0 23948 1148 960 S 13.0 0.3 15339:23 vmware-guestd 3840 root 20 0 19880 584 512 S 7.7 0.2 1729:17 hald-addon-stor This virtual guest state is ok ... If anyone has any ideas .. Thanks

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  • Ubuntu purple splash screen with blinking pixels?

    - by joxnas
    I had ubuntu 9.10 I upgraded to 10.04 after solving some problems (freeze at boot). Since then, I don't have the ubuntu's logo showing up when I boot, but a purple screen with some blinking pixels. I didn't care much about it... but today my computer took too long at that screen (normally it was just 1/4 second, but today it was like a minute..). And it happened like 4 or 5 times in a row (Only at the 5th time I realised that it was not freezing up, but it simply would took more time) After a reboot, it is again 1/4 second of purple screen but I don't want this problem to return.. so I want to get rid of the purple screen (I think it is an indicator of the problem) Well, I already installed the graphic drivers (going to system admnistration hardware drivers). But it didn't solve anything. (I don't know if it is even related) I searched in google, found something old (2006) and I think it maybe has some relation with my problems .. http://ubuntuforums.org/archive/index.php/t-294692.html But couldn't understand the conversation (i'm a linux novice) Sorry for my horrible english.. I would appreciate any help! My hardware: ATI Mobility Radeon 4650 HD P7450 2.13Ghz Core 2 Duo

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  • Join multiple filesystems (on multiple computers) into one big volume

    - by jm666
    Scenario: Have 10 computers, each have 12x2TB HDDs (currently) in raidZ2 (10+2) configuration, so, in the each computer i have one approx. 20TB volume. Now, need those 10 separate computers (separate raid groups) join into one big volume. What is the recommended solution? I'm thinking about the FCoE (10GB ethernet). So, buying into each computer FCoE (10GB ethernet card) and - what need more on the hardware side? (probably another computer, FCoE switch? like Cisco Nexus?) The main question is: what need to install and configure on each computer? Currently they have freebsd/raidz2, but it is possible change it into Linux/Solaris if needed. Any helpful resource what talking about how to build a big volumes from smaller raid-groups (on the software side) is very welcomed. So, what OS, what filesystem, what software - etc. In short: want get one approx. 200TB storage (in one filesystem) from already existing computers/storage. Don't need fast writes, but need good performance on reading data. (as a big fileserver), what will works transparently, so when storing data don't want care about onto what computer the data goes. (e.g. not 10 mountpoints - but one big logical filesystem). Thanks.

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  • Timely automatic unexpected reboot on ubuntu desktop

    - by ahmad
    We have a remote linux server (ubuntu desktop). The system log indicates the system has been restarted on the timely fashion. Here is a part of the last output: ut pts/0 192.169.50.2-sta Sat Nov 24 22:17 still logged in reboot system boot 2.6.32-21-generi Sat Nov 24 22:04 - 22:17 (00:13) ut pts/0 server.local Sat Nov 24 21:36 - crash (00:27) reboot system boot 2.6.32-21-generi Sat Nov 24 15:55 - 22:17 (06:21) reboot system boot 2.6.32-21-generi Fri Nov 23 18:02 - 22:17 (1+04:14) reboot system boot 2.6.32-21-generi Fri Nov 23 10:39 - 22:17 (1+11:38) reboot system boot 2.6.32-21-generi Fri Nov 23 04:18 - 22:17 (1+17:59) reboot system boot 2.6.32-21-generi Fri Nov 23 03:57 - 22:17 (1+18:20) reboot system boot 2.6.32-21-generi Thu Nov 22 20:38 - 22:17 (2+01:38) reboot system boot 2.6.32-21-generi Thu Nov 22 11:13 - 22:17 (2+11:03) reboot system boot 2.6.32-21-generi Thu Nov 22 08:12 - 22:17 (2+14:05) reboot system boot 2.6.32-21-generi Wed Nov 21 11:16 - 22:17 (3+11:00) reboot system boot 2.6.32-21-generi Tue Nov 20 22:36 - 22:17 (3+23:41) reboot system boot 2.6.32-21-generi Tue Nov 20 14:12 - 22:17 (4+08:05) reboot system boot 2.6.32-21-generi Tue Nov 20 11:32 - 22:17 (4+10:44) reboot system boot 2.6.32-21-generi Tue Nov 20 01:52 - 22:17 (4+20:25) reboot system boot 2.6.32-21-generi Tue Nov 20 00:22 - 22:17 (4+21:55) reboot system boot 2.6.32-21-generi Mon Nov 19 17:27 - 22:17 (5+04:50) It looks the system is set to be restarted at 22:17. Can anyone guide me why this happens? Thanks in advance.

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  • User http does not have write permissions directory?

    - by dwieeb
    I have a bit of an odd set up, I think. I have groups for each domain my server hosts, and I add the user http to each domain group along with the users that should have access to the groups' domains. In my php script running from a directory 'public_html', I try creating a file: <?php $output = ""; print exec('touch test 2>&1', $output); But I get touch: cannot touch `test': Permission denied and the file is not created. But here, clearly stated, the group has all permissions on the directory: drwxrwxr-x 5 dwieeb example.com 1024 Feb 4 05:19 public_html And here are the permissions on the php file in public_html that is trying to use the exec function: -rw-rw-r-- 1 dwieeb example.com 59 Feb 4 05:19 test.php How is this possible if http is part of the example.com group (as seen from a cat on /etc/group) and the directory has full permissions for the group? ... example.com:x:1000:dwieeb,http I'm stumped. EDIT (since apparently I'm not cool enough to answer my own questions yet): Ah, I found the problem. Yes, I restarted Nginx, but the php-fpm daemon must be restarted as well when http is added to the group for my domain. On Arch Linux: rc.d restart php-fpm

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  • Permission Denied for FTP User

    - by Alasdair
    I have an FTP user whose default is /root/ftpuser This user can login fine. The user is the owner of the directory & the directory is even set to 777 permissions. But the user can't upload anything, the display is: Status: Connecting to xx.xxx.xxx.xx:21... Status: Connection established, waiting for welcome message... Response: 220---------- Welcome to Pure-FTPd [privsep] [TLS] ---------- Response: 220-You are user number 2 of 50 allowed. Response: 220-Local time is now 05:12. Server port: 21. Response: 220-This is a private system - No anonymous login Response: 220-IPv6 connections are also welcome on this server. Response: 220 You will be disconnected after 15 minutes of inactivity. Command: USER ftpuser Response: 331 User ftpuser OK. Password required Command: PASS ********* Response: 230 OK. Current restricted directory is / Command: OPTS UTF8 ON Response: 200 OK, UTF-8 enabled Status: Connected Status: Starting upload of test.html Command: CWD / Response: 550 Can't change directory to /: Permission denied Command: MKD / Response: 550 Can't create directory: Permission denied Command: CWD / Response: 550 Can't change directory to /: Permission denied Command: SIZE /btn.png Response: 550 Can't check for file existence Command: TYPE I Response: 200 TYPE is now 8-bit binary Command: PASV Response: 227 Entering Passive Mode (66,232,106,33,52,218) Command: STOR /test.html Response: 553 Can't open that file: Permission denied Error: Critical file transfer error It's a Linux CentOS 6 server. Any ideas?

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  • How to create a new background process in a KSH "while read" loop?

    - by yael
    The following test script has a problem. When I add the line (sleep 5 ) & in the script then the "while read" loop does not read all lines from the file, but only prints the first line. But when I remove the ( sleep 5 ) & from the script, then the script prints all lines as defined in the file. Why the ( sleep 5 ) & causes this? And how to solve the problem? I want to create a new process (for which the sleep is just an example) in the while loop: $ more test #!/bin/ksh while read -r line ; do echo Read a line: echo $line ( sleep 5 )& RESULT=$! echo Started background sleep with process id $RESULT sleep 1 echo Slept for a second kill $RESULT echo Killed background sleep with process id $RESULT done < file echo Completed On my Linux, when using the following contents of file: $ more file 123 aaa 234 bbb 556 ccc ...running ./test just gives me: Read a line: 123 aaa Started background sleep with process id 4181 Slept for a second Killed background sleep with process id 4181 Completed

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  • Removing extended partition without deleting logical in it

    - by HisDudeness
    I'm running a Linux-based laptop, and in order to multi-boot several distros in it, I created an extended partition which contains a bunch of logical ones with GParted. Now, after quite a long time with this setup, I've changed my mind because of the consequent lack of storing space for my data partition. Now I want to keep one distro alone like it's normal, and eventually have some other operating systems stored in external supports to plug in and use if I want. Obviously, also this partition I want to keep (and to enlarge a little too) is just a logical inside the extended I want to keep. For what concerns the number I'm ok, meaning I currently have this big distro dedicated extended, the swap and the data partitions, so there's space for another primary before I delete the extended, but I don't know how to delete it without touching the logical in it, I don't want to reinstall the system losing all changes and settings, and I don't want to keep an extended partition for a logical alone. How can I do? Do I have to create a new primary, copy the logical content in it and then delete everything? Will the system boot and maintain exactly all the features it has now? Or is there a way to convert an extended into a primary once it contains just one logical? Or can I directly move a logical out of an extended turning it into a primary? Or, again, am I screwed?

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  • RAID 6 that can read with least 1000 Mbit/s?

    - by Diblo Dk
    I purchased a Dell PERC 6/i which I expected to be able to read with 1000 Mbps. There is not much to do now, but there are some things I wanted knowledge about for another time. I have configured it with four 2 TByte drives and RAID 6. It have 256 MByt ram and transfer rate of 300 Mbps. The benchmark test showed: Min read rate: 136.3 Mbps Max read rate: 329,6 Mbps Avg read rate: 242,2 Mbps What could I had done to get at least 1000 Mbps? Is it normal for internal and external RAID controllers to have a lower transfer rate eg. 300 Mbps? (I did not noticed at the time that it was not 3 Gbps) How would a RAID 10 had performed compared to RAID 6 or 5? Would it have been better to use software RAID (Linux) with the internal 3 Gbps SATA controller? UPDATE: The drives is SATA III 6 Gbps. http://www.seagate.com/files/staticfiles/docs/pdf/datasheet/disc/desktop-hdd-data-sheet-ds1770-1-1212us.pdf (2TB)

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  • How can I prevent a DDOS attack on Amazon EC2?

    - by cwd
    One of the servers I use is hosted on the Amazon EC2 cloud. Every few months we appear to have a DDOS attack on this sever. This slows the server down incredibly. After around 30 minutes, and sometimes a reboot later, everything is back to normal. Amazon has security groups and firewall, but what else should I have in place on an EC2 server to mitigate or prevent an attack? From similar questions I've learned: Limit the rate of requests/minute (or seconds) from a particular IP address via something like IP tables (or maybe UFW?) Have enough resources to survive such an attack - or - Possibly build the web application so it is elastic / has an elastic load balancer and can quickly scale up to meet such a high demand) If using mySql, set up mySql connections so that they run sequentially so that slow queries won't bog down the system What else am I missing? I would love information about specific tools and configuration options (again, using Linux here), and/or anything that is specific to Amazon EC2. ps: Notes about monitoring for DDOS would also be welcomed - perhaps with nagios? ;)

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  • Software RAID 1 Configuration

    - by Corve
    I have created a software RAID 1 quite some while ago and it always seemed to work for me. However I am not completely sure that I have configured everything right and do not have the experience to check so I would be very grateful for some advice or just verification that all seems right so far. I am using Linux Fedora 20 (32 bit with plans to upgrade to 64bit) The RAID 1 should consist of two 1TB SATA hard drives. This is the output of mdadm --detail /dev/md0 /dev/md0: Version : 1.2 Creation Time : Sun Jan 29 11:25:18 2012 Raid Level : raid1 Array Size : 976761424 (931.51 GiB 1000.20 GB) Used Dev Size : 976761424 (931.51 GiB 1000.20 GB) Raid Devices : 2 Total Devices : 1 Persistence : Superblock is persistent Update Time : Sat Jun 7 10:38:09 2014 State : clean, degraded Active Devices : 1 Working Devices : 1 Failed Devices : 0 Spare Devices : 0 Name : argo:0 (local to host argo) UUID : 1596d0a1:5806e590:c56d0b27:765e3220 Events : 996387 Number Major Minor RaidDevice State 0 0 0 0 removed 1 8 0 1 active sync /dev/sda The RAID is mounted successfully: friedrich@argo:~ ? sudo mount -l | grep md0 /dev/md0 on /mnt/raid type ext4 (rw,relatime,data=ordered) Basically my question are: Why do I only have 1 active device? What does the State removed at bottom mean? Also I noticed some strange error messages that I see on the console on system start and shutdown and always repeating in the background when I switch with Ctrl + Alt + F2: ... ata2: irq_stat 0x00000040 connection status changed ata2: SError: { CommWake DevExch } ata2: COMRESET failed (errno=-32) ata2: exception Emask 0x10 SAct 0x0 SErr 0x4040000 action 0xe frozen ata2: irq_stat 0x00000040 connection status changed ata2: SError: { CommWake DevExch } ata2: exception Emask 0x10 SAct 0x0 SErr 0x4040000 action 0xe frozen ... Are these errors related to the RAID? Something seems wrong with the SATA devices.. All together the system works (I can read and write to the mounted raid) but I always had these strange errors on startup shutdown (probably always in the background). Thx for your help

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  • Starting multiple Chrome full screen instances on multiple monitors from (batch) script

    - by Bob Groeneveld
    My goal is to show different web content full screen on multiple monitors automatically after booting from a single computer. The browser I would like to use is Chrome. If Chrome does not support this and Firefox does that would be fine. The OS I would prefer is Windows, if it turns out that Linux is possible that would be fine. On Windows it is possible to set the position of the Chrome browser window (--window-position=) and make Chrome start in full screen mode (--kiosk). Using these options combined you can start Chrome full screen on any of the desktops/screens that you have connected to your computer. I have managed to get this working. However, if I then try to do the same thing a second time to have Chrome full screen on a second screen the second Chrome window will open over the first window, no matter the coordinates I use for the --window-position parameter. I have tried using Chrome profiles and copying the Chrome directory and starting the second chrome.exe. All these things result in the same behaviour.

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  • Trouble getting started with the STEALTH monitoring package

    - by dlanced
    Is anyone here familiar with the Linux-based STEALTH package (for monitoring FS integrity of client systems)? I'm trying to get started with a very simple configuration, but I'm running into trouble (this is running under Ubuntu 14.04): Config line `USE BASE/root/stealth/10.0.0.79' invalid STEALTH (2.11.02) started at Fri, 30 May 2014 15:25:00 +0000 Program terminated due to non-zero exit value for -type f -exec /usr/bin/sha1sum {} \; (EOC Fri May 30 15:25:00 2014 127) Stealth is creating a binary tmp file in the Stealth server root and generating a "report" file in the start directory, but not much else. Regarding the "USE BASE...invalid" error, and just to be sure, I manually created the directories in /root, but it didn't help. And, by the way, I am running stealth with sudo. Everything seems to be configured correctly: I'm able to ssh into root@client from the stealth machine without a password Here's my "policy" file (I've removed the email directives just for simplicity): DEFINE SSHCMD /usr/bin/ssh [email protected] -T -q exec /bin/bash --noprofile DEFINE EXECSHA1 -xdev -perm +u+s,g+s ( -user root -or -group root ) \ -type f -exec /usr/bin/sha1sum {} \; USE BASE/root/stealth/10.0.0.79 USE SSH ${SSHCMD} USE DD /bin/dd USE DIFF /usr/bin/diff USE PIDFILE /var/run/stealth- USE REPORT report USE SH /bin/sh GET /usr/bin/sha1sum /root/tmp LABEL \nchecking the client's /usr/bin/find program CHECK LOG = remote/binfind /usr/bin/sha1sum /usr/bin/find LABEL \nsuid/sgid/executable files uid or gid root on the / partition CHECK LOG = remote/setuidgid /usr/bin/find / ${EXECSHA1} LABEL \nconfiguration files under /etc CHECK LOG = remote/etcfiles \ /usr/bin/find /etc -type f -not -perm /6111 \ -not -regex "/etc/(adjtime\|mtab)"\ -exec /usr/bin/sha1sum {} \; Any ideas? Thanks,

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  • Solution to easily share large files with non-tech-savvy users?

    - by Tim
    Hey all, We've got a server setup at work which we'd like to use to exchange large files with known clients easily. We're looking into software to facilitate this, but somewhow typing "large file hosting" into Google gives questionable results.. ;) We've come up with the following requirements, and I hope any of you can points us in the direction of a solution that offers this functionality, or is malleable to our needs. Synchronization / revision management is of no concern, it's mostly single large (up to 1+ GB) file uploads & downloads we'll need. We'd like to make the downloads expire & be removed after a certain number of days / downloads, to limit the amount of cleanup we'd have to do. The data files exchanged sometimes hold confidential information, so the URLs generated should be random and not publicly visible. Our users are of the less technically savvy variety, so a simple webform would be best over a desktop client (because we also have to support a mix of operating systems). As for use of the system we'd either like to send out generated random URLs for them to upload their files, or have an easy way manage & expire users. Works on a linux (Ubuntu) server (so nothing .Net-related please) Does anyone know of software that fits the above criteria? We've already seen a few instances of this within the scientific community, but nothing we could use directly.. Best regards, Tim

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  • Solution to easily share large files with non-tech-savvy users?

    - by Tim
    Hey all, We've got a server setup at work which we'd like to use to exchange large files with known clients easily. We're looking into software to facilitate this, but somewhow typing "large file hosting" into Google gives questionable results.. ;) We've come up with the following requirements, and I hope any of you can points us in the direction of a solution that offers this functionality, or is malleable to our needs. Synchronization / revision management is of no concern, it's mostly single large (up to 1+ GB) file uploads & downloads we'll need. We'd like to make the downloads expire & be removed after a certain number of days / downloads, to limit the amount of cleanup we'd have to do. The data files exchanged sometimes hold confidential information, so the URLs generated should be random and not publicly visible. Our users are of the less technically savvy variety, so a simple webform would be best over a desktop client (because we also have to support a mix of operating systems). As for use of the system we'd either like to send out generated random URLs for them to upload their files, or have an easy way manage & expire users. Works on a linux (Ubuntu) server (so nothing .Net-related please) Does anyone know of software that fits the above criteria? We've already seen a few instances of this within the scientific community, but nothing we could use directly.. Best regards, Tim

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  • Plesk FTP not working but SFTP and Shell is working

    - by shamittomar
    I am facing a strange problem. The FTP on my Plesk VPS is not working. Whenever I try to connect, FileZilla FTP client says: Status: Resolving address of xxxxxxxxxxxxx.com Status: Connecting to xxx.xxx.xxx.xxx:21... Status: Connection established, waiting for welcome message... Error: Could not connect to server So, it's not even going to the step of asking username/password. So, it's something else. The SFTP on port 22 is working fine. Also, I can successfully do shell access and run commands. But, I NEED FTP access too on port 21. I have searched everywhere but can not find any setting to enable it. This is the Plesk version info: Parallels Plesk Panel version 9.5.2 Operating system Linux 2.6.26.8-57.fc8 CPU GenuineIntel, Intel(R) Pentium(R) 4 CPU 3.00GHz Any help is appreciated. [EDIT]: The firewall is not blocking it. I have checked it on server and there are absolutely no blocking rule. Firewall states: All incoming/outgoing connections are accepted on FTP And on client-side (my PC), I can connect to other FTP servers so this is not an issue in my PC's firewall. Moreover, I can not even connect to the FTP from online FTP clients like net2ftp.

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  • How to set umask globally?

    - by DevSolar
    I am using a private user group setup, i.e. a user foo's home directory is owned by foo:foo, not foo:users. For this to work, I need to set the umask to 002 globally. After a quick grep -RIi umask /etc/*, it seemed for a moment that modifying the UMASK entry in /etc/login.defs should do the trick. It does, too -- but only for console logins. If I log in to my desktop, and open a terminal there, I still get to see the default umask 022. Same goes for files created from apps started through the menu. Apparently, the display manager (or whatever X11 component responsible) does source some different setting than a console login does, and damned if I could tell which one it is. (I tried changing the setting in /etc/init.d/rc, and no, it did not help.) How / where do I set umask globally (and for all users), so that the X11 desktop environment gets the memo as well? (The system is Linux Mint / Ubuntu, in case that changes anything...)

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  • TCP Keepalive and firewall killing idle sessions

    - by Carlos A. Ibarra
    In a customer site, the network team added a firewall between the client and the server. This is causing idle connections to get disconnected after about 40 minutes of idle time. The network people say that the firewall doesn't have any idle connection timeout, but the fact is that the idle connections get broken. In order to get around this, we first configured the server (a Linux machine) with TCP keepalives turned on with tcp_keepalive_time=300, tcp_keepalive_intvl=300, and tcp_keepalive_probes=30000. This works, and the connections stay viable for days or more. However, we would also like the server to detect dead clients and kill the connection, so we changed the settings to time=300,intvl=180,probes=10, thinking that if the client was indeed alive, the server would probe every 300s (5 minutes) and the client would respond with an ACK and that would keep the firewall from seeing this as an idle connection and killing it. If the client was dead, after 10 probes, the server would abort the connection. To our surprise, the idle but alive connections get killed after about 40 minutes as before. Wireshark running on the client side shows no keepalives at all between the server and client, even when keepalives are enabled on the server. What could be happening here? If the keepalive settings on the server are time=300,intvl=180,probes=10, I would expect that if the client is alive but idle, the server would send keepalive probes every 300 seconds and leave the connection alone, and if the client is dead, it would send one after 300 seconds, then 9 more probes every 180 seconds before killing the connection. Am I right? One possibility is that the firewall is somehow intercepting the keepalive probes from the server and failing to pass them on to the client, and the fact that it got a probe makes it think that the connection is active. Is this common behavior for a firewall? We don't know what kind of firewall is involved. The server is a Teradata node and the connection is from a Teradata client utility to the database server, port 1025 on the server side, but we have seen the same problem with an SSH connection so we think it affects all TCP connections.

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  • Getting Started in SuSE as an Ubuntu User

    - by Subhamoy Sengupta
    I am not a Linux newbie, but haven't touched SuSE in a very very long time (last time I tried it, it was SuSE 7!). Finally now I felt like giving it a try, and many things seem strange or unnecessarily complex. I have a series of questions. How do I ensure that my packages are uptodate? It sounds silly, but I tried the obvious methods already. I have disabled the default repositories that show up when you do zypper lr, and added Tumbleweed and packman repositories (Essentials, Multimedia, Extra). Then I did a sudo zypper ref --force and then sudo zypper dup, and it tells me many dependencies are not met. I have already added solder.allowVendorChange=true to /etc/zypp/zypp.conf, so it should not care which repository the latest versions are in, and just upgrade to it. Even when I chose to skip the packages with unmet dependencies, and seemed like quite a bit happened in the background, I opened Firefox afterwards and the version was 7! I am guessing things did not go as expected. But of course this is not a problem with SuSE, but I am not understanding the system right. How do I do it right? When I start typing arguments of a command, for example sudo zypper install, when I type sudo zypper ins and keep hitting TAB, nothing happens! It always worked in Ubuntu and I feel very uneasy with this. Is this how SuSE is supposed to be? When I try to install something, and I start writing its name, even though the package exists and I am sure of it, hitting TAB does not autocomplete it. This is also quite inconvenient. Why is it not happening? There are many things in SuSE that are really great, and I think I will stay with it and not go back to Ubuntu once I settle these very rudimentary issues. But right now they are giving me a lot of grief! Please help!

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  • Intermittently uncommunicative subnets

    - by mhd
    Last week proved me a veritable Cassandra: I've always said that it's a bad idea to have only one firewall/router, without a backup or failover. And thus our Cisco PIX went haywire, refusing to route properly. And of course, the only one available here on short notice is me, and while I'm quite grounded in Linux, I'm really a developer not a sysadmin (the fact that this hit me on sysadmin appreciation day is a bit ironic). Anyway, this weekend I tried to hack up a temporary solution: I used an old server with enough NICs (two built-in, four on a card) to serve as a gateway and firewall. Due to some problems with the raid controller, I got only two router distros running, and between Untangle and Ebox I decided for the latter. Now everything is quite okay. I've got all the different subnets we've got here (all with separate switches) talking to each other and even to the internet (Cisco 2800 router, T1 lines). But from time to time (20-60 minute intervals), I get a total routing failure. Our main, office subnet can't talk to our server subnet and can't connect to the internet. This is not the end of a gradual slowdown, either everything's working perfectly or I get a total lack of communication for about two minutes each time. Now I'm a bit at wits end what to check. At least with the default EBox setup, nothing in /var/log shows anything weird and it doesn't exactly have lots of built-in monitoring tools. So I'm hoping someone here could give me some pointers about what to look out for. I did change the ethernet cable from the office switch to the firewall, with no results. I might change switches, although within the switch it seems to work ok enough. Edit: I'm not sure whether this is the sole cause of the problem, but after I noticed a few DHCP entries just before the last drop of connectivity, I tried to reproduce that. And alas, whenever I renew a DHCP connection, I can't access other subnets anymore. Running ISC DHCPD 3.0.6.

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  • How to completely disable IPv6 for loopback interface on RHEL 5.6

    - by Marc D
    I've done lots of research on how to disable IPv6 on RedHat Linux and I have it almost completely disabled. However the loopback interface is still getting an inet6 loopback address (::1/128). I can't find where IPV6 is still enabled for loopback. To disable IPV6 I added the following settings to /etc/sysctl.conf: net.ipv6.conf.default.disable_ipv6=1 net.ipv6.conf.all.disable_ipv6=1 And also added the following line to /etc/sysconfig/network: NETWORKING_IPV6=no After rebooting, the inet6 address is gone from my physical interface (eth0), but is still there for lo: # ip addr show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000 link/ether 00:50:56:xx:xx:xx brd ff:ff:ff:ff:ff:ff inet 10.x.x.x/21 brd 10.x.x.x scope global eth0 If I manually remove the IPV6 address from loopback and then bounce the interface, it comes back: # ip addr del ::1/128 dev lo # ip addr show lo 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo # ip link set lo down # ip link set lo up # ip addr show lo 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo inet6 ::1/128 scope host valid_lft forever preferred_lft forever I believe IPV6 should be disabled at the kernel level as confirmed by sysctl: # sysctl net.ipv6.conf.lo.disable_ipv6 net.ipv6.conf.lo.disable_ipv6 = 1 Any ideas on what else would cause the loopback interface to get an IPV6 address?

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  • DHCPD (Slackware) - Disabling auto-generation of gateway as DNS server

    - by Dogbert
    Good day, I am using a Linux workstation on Slackware 13.37. One "problem" I have had to deal with ever since 11.0 is the following: DNS servers are queried and determined at startup by DHCP daemon (DHCPD) This is invoked at startup by a script located at /etc/rc.d/rc.dhcpd My DNS servers for my ISP are resolved correctly, and are stored in a list located at /etc/resolv.conf However, the one annoying problem is that my gateway IP (ie: 192.168.1.1) is always automatically put at the top of the list in resolv.conf, meaning I have to always wait for a timeout before a valid DNS server is used to resolve an address (ie: timeout on 192.168.1.1 because it is not actually a DNS server, then DHCP uses the next server in the list). I could lower my DNS resolution timeout so the gateway query times out quicker, but that's not what I want, as I don't want to degrade the abilities of legitimate DNS servers. What I would like to do is change how DHCPD operates so that it does NOT put my gateway IP address at the beginning of this list. I've searched via "man dhcpd", etc, and haven't found the exact answer yet. Any help on this issue is appreciated. Thank you all in advance for your time and assistance.

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  • Virtualizing an Inline network appliance with VirtualBox (or VMWare)

    - by Tzury Bar Yochay
    My device, which is a Linux based IP in-liner is transparent to the network peripherals, that is, no IP address assigned to any of its interfaces. For the sake of the conversation, let's use ADSL connection as an example, while the device is inspecting the bi-directional traffic, the network is behaving same as if device was not there, attached to the wire (see Physical setup at the attached diagram). I wonder if I can enclosed that "device" within a Windows machine and have it operated virtually so it still seats inline between the ADSL router and the Windows netwroking interface by using virtual NICs, (or whatever their name is in windows), and inspecting the traffic, same as if it was on a separate physical device, the drawing under "Virtual Setup" in the attached diagram show what I am trying to achieve. Reading a bit on the VirtualBox docs, seems like binding the right side is relatively simple, perhaps I should have one network adapter set as Bridge Networking and VirtualBox will connect it to the physical NIC on the host machine, and network packets are exchanged directly, circumventing the host operating system's network stack (WinXP in my case). However, I have no idea how to achieve the left side of my diagram, which requires adding virtual NICs to windows and configure them correctly in a way to make that pipeline possible. I would appreciate any help. by the way, if that is not possible with VirtualBox but with other virtualization solution (e.g. VMWare), I would accept the other as well.

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  • Start Chrome by command line, but adding some arguments to make it login into your Google account automatically

    - by jim
    Is there a way to start Chrome calling it from the command line (using Linux), but providing it some argument to make it login into some Google account automatically? I'm looking for something like google-chrome -account foo -pass bar that I can easily put in a bash script later. A little background: I have a laptop connected to my TV, which is currently using just a mouse for user interaction. There's no google account logged in by default, and that's the way I want to keep it, so my kids can't come across videos and pictures in google and youtube that they are not supposed to see (e.g.: adult content, or anything marked as not appropriate for kids by the google's safe search filters). The bad thing about this is that there are some music videos in youtube that requires you to be logged in to see, usually those we (the adults) used to sing when playing karaoke... as the only input available is a mouse, I'm looking for a way to start with my google account without having to type the whole thing usin the on-screen keyboard. You may think "Why you can't use the keyboard, if the laptop is right there?". Well, it's in a kind of uncomfortable position - too high for me without a chair or something, as it's right above the furniture in where the TV is located. Is there a way to make this scriptable? If not, do you know any other workaround? Note: using the remember me after logging off or alike options are discarded, as the safe-search chrome version must be always the default version to run.

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