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  • S#arp Architecture 1.5 Beta 1 released

    - by AlecWhittington
    Well it is official, I just finished my first release for S#arp Architecture . While this is only a beta release, it does contain some big upgrades and we are hoping to get any bugs handled quickly so that we can get the RTM release completed. This will be a short post, with a more detailed posts coming in the next few days. A big thanks goes out to Billy McCafferty , Michael Aird, Hoang Tang, and everyone else that had a say in this release. Release notes Built on top of ASP.NET MVC 2 RTM release...(read more)

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  • Host spreads wrong MAC Adress of router on the WIFI

    - by JavaIsMyIsland
    Strange things are going on our network. Since yesterday a host which is actually not on our subnet spreads wrong ARP Replys on our network. To be precise, only on the WIFI. If I connect my Laptop to the cable ethernet, it gets the right MAC adress of the router. Also my Android phone and my Ubuntu system do get the right MAC Adress. So I took a look at wireshark. When I clear the ARP cache of the windows machine, the first ARP response is correct and comes from the router. But like 10 ms later another ARP response comes from another host in the WIFI. The host changes its IP Adresses from time to time and they look like they are not on our subnet. So I can not use the internet because DNS is not working anymore. Sometimes the router wins the race condition and the mac adress is set correctly in the arp cache. I first thought, this is an arp-poisoning mitm attack but it does not make sense if the packets get not routed correctly?! I restarted the router but it didn't help. I have no access to the router, else I would change the shared key to make sure there is no intruder on the wifi.

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  • linux routing bug?

    - by Balázs Pozsár
    I have been struggling with this not easily reproducible issue since a while. I am using linux kernel v3.1.0, and sometimes routing to a few IP addresses does not work. What seems to happen is that instead of sending the packet to the gateway, the kernel treats the destination address as local, and tries to gets its MAC address via ARP. For example, now my current IP address is 172.16.1.104/24, the gateway is 172.16.1.254: # ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:1B:63:97:FC:DC inet addr:172.16.1.104 Bcast:172.16.1.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:230772 errors:0 dropped:0 overruns:0 frame:0 TX packets:171013 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:191879370 (182.9 Mb) TX bytes:47173253 (44.9 Mb) Interrupt:17 # route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 172.16.1.254 0.0.0.0 UG 0 0 0 eth0 172.16.1.0 0.0.0.0 255.255.255.0 U 1 0 0 eth0 I can ping a few addresses, but not 172.16.0.59: # ping -c1 172.16.1.254 PING 172.16.1.254 (172.16.1.254) 56(84) bytes of data. 64 bytes from 172.16.1.254: icmp_seq=1 ttl=64 time=0.383 ms --- 172.16.1.254 ping statistics --- 1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev = 0.383/0.383/0.383/0.000 ms root@pozsybook:~# ping -c1 172.16.0.1 PING 172.16.0.1 (172.16.0.1) 56(84) bytes of data. 64 bytes from 172.16.0.1: icmp_seq=1 ttl=63 time=5.54 ms --- 172.16.0.1 ping statistics --- 1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev = 5.545/5.545/5.545/0.000 ms root@pozsybook:~# ping -c1 172.16.0.2 PING 172.16.0.2 (172.16.0.2) 56(84) bytes of data. 64 bytes from 172.16.0.2: icmp_seq=1 ttl=62 time=7.92 ms --- 172.16.0.2 ping statistics --- 1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev = 7.925/7.925/7.925/0.000 ms root@pozsybook:~# ping -c1 172.16.0.59 PING 172.16.0.59 (172.16.0.59) 56(84) bytes of data. From 172.16.1.104 icmp_seq=1 Destination Host Unreachable --- 172.16.0.59 ping statistics --- 1 packets transmitted, 0 received, +1 errors, 100% packet loss, time 0ms When trying to ping 172.16.0.59, I can see in tcpdump that an ARP req was sent: # tcpdump -n -i eth0|grep ARP tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes 15:25:16.671217 ARP, Request who-has 172.16.0.59 tell 172.16.1.104, length 28 and /proc/net/arp has an incomplete entry for 172.16.0.59: # grep 172.16.0.59 /proc/net/arp 172.16.0.59 0x1 0x0 00:00:00:00:00:00 * eth0 Please note, that 172.16.0.59 is accessible from this LAN from other computers. Does anyone have any idea of what's going on? Thanks. update: replies to the comments below: there are no interfaces besides eth0 and lo the ARP req cannot be seen on the other end, but that's how it should work. the main problem is that an ARP req should not even be sent at the first place the problem persist even if I add an explicit route with the command "route add -host 172.16.0.59 gw 172.16.1.254 dev eth0"

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  • Routing and arp

    - by adolgarev
    If I have >ip ro 192.168.14.0/24 dev eth0 another host can obtain my mac address. But if I flush routing info: >ip ro flush table main arp resolution doesn't work. Broadcast packets "Who has 192.168.14.149" reach eth0 but OS (Linux) doesn't respond despite eth0 has address 192.168.14.149. What connection exists between routing and arp resolution?

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  • linux container bridge filters ARP reply

    - by Dani Camps
    I am using kernel 3.0, and I have configured a linux container that is bridged to a tap interface in my host computer. This is the bridge configuration: :~$ brctl show bridge-1 bridge name bridge id STP enabled interfaces bridge-1 8000.9249c78a510b no ns3-mesh-tap-1 vethjUErij My problem is that this bridge is dropping ARP replies that come from the ns3-mesh-tap-1 interface. Instead, if I statically populate the ARP tables and ping directly everything works, so it has to be something related to ARP. I have read about similar problems in related posts, and I have tried with the solutions explained therein but nothing seems to work. Specifically: ~$ grep net.bridge /etc/sysctl.conf net.bridge.bridge-nf-call-arptables = 0 net.bridge.bridge-nf-call-iptables = 0 net.bridge.bridge-nf-call-ip6tables = 0 net.bridge.bridge-nf-filter-vlan-tagged = 0 net.bridge.bridge-nf-filter-pppoe-tagged = 0 arptables and ebtables are not installed. iptables FORWARD is all set to accept: Chain FORWARD (policy ACCEPT) target prot opt source destination The bridged interfaces are set to PROMISC: ~$ ifconfig ns3-mesh-tap-1 Link encap:Ethernet HWaddr 1a:c7:24:ef:36:1a ... UP BROADCAST PROMISC MULTICAST MTU:1500 Metric:1 vethjUErij Link encap:Ethernet HWaddr aa:b0:d1:3b:9a:0a .... UP BROADCAST RUNNING PROMISC MULTICAST MTU:1500 Metric:1 The macs learned by the bridge are correct (checked with brctl showmacs). Any insight on what I am doing wrong would be greatly appreciated. Best Regards Daniel

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  • Ubuntu 12 crashed and took down network

    - by Leopd
    We recently set up a new Ubuntu 12.04LTS server on our network. It's not fully configured so it's not doing much beyond sshd and a default apache2 install. But this evening it appears to have crashed. It wasn't responding to the network or the keyboard. But the worst part is, it took down the entire network. My knowledge of the network stack below OSI layer 3 is very limited, so the rest confuses me. When this machine was physically connected to the network, no other machine could connect to the outside internet. When things were broken, running arp showed that our gateway's IP address (10.0.1.1) was listed as "invalid." Unplugging the server from the network fixed the problem, and plugging it back in broke it again. So the crashed server was advertising itself as owning the gateway's IP address? There's nothing at all in syslog during the time when it was causing problems. Any ideas about how to figure out what went wrong or what we can do to prevent it from happening again? I'm hesitant to even put the machine back on the network right now. Update ** It crashed again, and I ran tcpdump -penn arp (thanks bahamat!) for several minutes and got this... (timestamps and duplicate lines removed) 00:1e:65:f8:dc:24 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 10.0.1.1 tell 10.0.2.191, length 46 00:1e:65:f8:dc:24 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 10.0.1.44 tell 10.0.2.191, length 46 60:d8:19:d4:71:d6 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 10.0.1.1 tell 10.0.2.125, length 46 d4:9a:20:04:e9:78 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Request who-has 192.168.1.1 tell 192.168.1.100, length 28 Update 2 ** When the network is functioning properly, arping -c4 10.0.1.1 returns this: ARPING 10.0.1.1 60 bytes from c0:c1:c0:77:25:8e (10.0.1.1): index=0 time=267.982 usec 60 bytes from c0:c1:c0:77:25:8e (10.0.1.1): index=1 time=422.955 usec 60 bytes from c0:c1:c0:77:25:8e (10.0.1.1): index=2 time=299.215 usec 60 bytes from c0:c1:c0:77:25:8e (10.0.1.1): index=3 time=366.926 usec --- 10.0.1.1 statistics --- 4 packets transmitted, 4 packets received, 0% unanswered (0 extra) When the bad server is plugged in, arping -c4 10.0.1.1 returns: ARPING 10.0.1.1 --- 10.0.1.1 statistics --- 4 packets transmitted, 0 packets received, 100% unanswered (0 extra) Context ** 10.0.x.x is the main subnet. 10.0.1.1 is the main internet gateway 10.0.1.44 is a printer 10.0.2.* devices are all laptops / workstations I have no idea what's using the 192.168.x.x subnet -- your guesses are at least as good as mine. A VM on a workstation? A misconfigured WAP? Somebody re-sharing wifi? A machine that failed to DHCP? The offending ubuntu server's MAC address ends in cd:80 so isn't listed in the dump. It should DHCP to 10.0.3.3 Thanks for any help. This ARP stuff is all voodoo to me. Packets just go to IP addresses, right? ;)

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  • SSH to remote host (edgemarc 4200 or 4500 series routers) and pull arp data

    - by MaQleod
    I've been trying to think of a method to do this for days, but have not come up with anything yet. Ideally, this is what I'm looking to do: From a windows XP machine, I need to open an SSH connection to a remote host, send the arp command, and pull the text results of the command back for use on the client. I will need to parse this data and preferably produce a 2D array of IPs and MAC addresses. There will be no shared keys, this is all done with a username and password that will always be different, they will need to be fed into the command via variables that will be pulled from a database using an autoit script based on the WAN ip of the remote host. Now the actual parsing of the data and creation of the array will be easy if I can just get the text of the arp table. Is there any way to ssh to a remote host, run a command and return the data from that command to the client in a batch script or perl script (it is ok if it writes the text to a file, I can read it out of the file later, I just need it to get to the client)?

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  • Is it possible to use the same MAC address for an entire subnet?

    - by Bruce
    I wish to add static entries to the ARP table of my machine so that it uses a dummy MAC 00:11:22:33:44:55 for any IP address within the subnet 10.0.0.0/8 Using arp -s 10.0.0.0/8 00:11:22:33:44:55 does not work. What can I do? PS - I know it might sound strange why anyone would want to do this but kindly bear with me here. EDIT: I am using this so that the hosts do not send a broadcast ARP message. I route the packets to the appropriate last hop router which changes the dst MAC from the fake MAC to the MAC of the dst IP address. I can get everything working except I have to manually enter the fake MAC for each subnet IP address.

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  • Troubleshooting PXE-E11: ARP Timeout error under VMware ESXi 4 and HPSA 7.8

    - by warren
    I am running HP Server Automation v7.8 in a lab environment on VMware ESXi, managed via vSphere 4. On the same host I have several small VMs for OS provisioning testing (512MB RAM, 10GB hdd, one NIC on the same vSwitch that HPSA is running on). DHCP is configured to hand-out addresses in the 192.168.10.151-200 range. On boot of the VM, it receives an IP (eg 192.168.10.198) within seconds. However, after it receives its IP, a PXE-E11: ARP Timeout error occurs in trying to boot from the DHCP server. I do not know if this is a HPSA-specific error, as I have seen reports of the PXE-E11 error on various forums. Proposed solutions I have seen so far (changing VLAN settings, for example) have not been applicable to my environment. Are there any pointers/troubleshooting steps that can be taken to resolve this?

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  • Cannot determine ethernet address for proxy ARP on PPTP

    - by Linux Intel
    I installed pptp server on a centos 6 64bit server PPTP Server ip : 55.66.77.10 PPTP Local ip : 10.0.0.1 Client1 IP : 10.0.0.60 centos 5 64bit Client2 IP : 10.0.0.61 centos5 64bit PPTP Server can ping Client1 And client 1 can ping PPTP Server PPTP Server can ping Client2 And client 2 can ping PPTP Server The problem is client 1 can not ping Client 2 and i get this error also on PPTP server error log Cannot determine ethernet address for proxy ARP Ping from Client2 to Client1 PING 10.0.0.60 (10.0.0.60) 56(84) bytes of data. --- 10.0.0.60 ping statistics --- 6 packets transmitted, 0 received, 100% packet loss, time 5000ms route -n on PPTP Server Destination Gateway Genmask Flags Metric Ref Use Iface 10.0.0.60 0.0.0.0 255.255.255.255 UH 0 0 0 ppp0 10.0.0.61 0.0.0.0 255.255.255.255 UH 0 0 0 ppp1 55.66.77.10 0.0.0.0 255.255.255.248 U 0 0 0 eth0 10.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 eth0 0.0.0.0 55.66.77.19 0.0.0.0 UG 0 0 0 eth0 route -n On Client 1 Destination Gateway Genmask Flags Metric Ref Use Iface 10.0.0.1 0.0.0.0 255.255.255.255 UH 0 0 0 ppp0 55.66.77.10 70.14.13.19 255.255.255.255 UGH 0 0 0 eth0 10.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 eth1 0.0.0.0 70.14.13.19 0.0.0.0 UG 0 0 0 eth0 route -n On Client 2 Destination Gateway Genmask Flags Metric Ref Use Iface 10.0.0.1 0.0.0.0 255.255.255.255 UH 0 0 0 ppp0 55.66.77.10 84.56.120.60 255.255.255.255 UGH 0 0 0 eth1 10.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 eth0 0.0.0.0 84.56.120.60 0.0.0.0 UG 0 0 0 eth1 cat /etc/ppp/options.pptpd on PPTP server ############################################################################### # $Id: options.pptpd,v 1.11 2005/12/29 01:21:09 quozl Exp $ # # Sample Poptop PPP options file /etc/ppp/options.pptpd # Options used by PPP when a connection arrives from a client. # This file is pointed to by /etc/pptpd.conf option keyword. # Changes are effective on the next connection. See "man pppd". # # You are expected to change this file to suit your system. As # packaged, it requires PPP 2.4.2 and the kernel MPPE module. ############################################################################### # Authentication # Name of the local system for authentication purposes # (must match the second field in /etc/ppp/chap-secrets entries) name pptpd # Strip the domain prefix from the username before authentication. # (applies if you use pppd with chapms-strip-domain patch) #chapms-strip-domain # Encryption # (There have been multiple versions of PPP with encryption support, # choose with of the following sections you will use.) # BSD licensed ppp-2.4.2 upstream with MPPE only, kernel module ppp_mppe.o # {{{ refuse-pap refuse-chap refuse-mschap # Require the peer to authenticate itself using MS-CHAPv2 [Microsoft # Challenge Handshake Authentication Protocol, Version 2] authentication. require-mschap-v2 # Require MPPE 128-bit encryption # (note that MPPE requires the use of MSCHAP-V2 during authentication) require-mppe-128 # }}} # OpenSSL licensed ppp-2.4.1 fork with MPPE only, kernel module mppe.o # {{{ #-chap #-chapms # Require the peer to authenticate itself using MS-CHAPv2 [Microsoft # Challenge Handshake Authentication Protocol, Version 2] authentication. #+chapms-v2 # Require MPPE encryption # (note that MPPE requires the use of MSCHAP-V2 during authentication) #mppe-40 # enable either 40-bit or 128-bit, not both #mppe-128 #mppe-stateless # }}} # Network and Routing # If pppd is acting as a server for Microsoft Windows clients, this # option allows pppd to supply one or two DNS (Domain Name Server) # addresses to the clients. The first instance of this option # specifies the primary DNS address; the second instance (if given) # specifies the secondary DNS address. #ms-dns 10.0.0.1 #ms-dns 10.0.0.2 # If pppd is acting as a server for Microsoft Windows or "Samba" # clients, this option allows pppd to supply one or two WINS (Windows # Internet Name Services) server addresses to the clients. The first # instance of this option specifies the primary WINS address; the # second instance (if given) specifies the secondary WINS address. #ms-wins 10.0.0.3 #ms-wins 10.0.0.4 # Add an entry to this system's ARP [Address Resolution Protocol] # table with the IP address of the peer and the Ethernet address of this # system. This will have the effect of making the peer appear to other # systems to be on the local ethernet. # (you do not need this if your PPTP server is responsible for routing # packets to the clients -- James Cameron) proxyarp # Normally pptpd passes the IP address to pppd, but if pptpd has been # given the delegate option in pptpd.conf or the --delegate command line # option, then pppd will use chap-secrets or radius to allocate the # client IP address. The default local IP address used at the server # end is often the same as the address of the server. To override this, # specify the local IP address here. # (you must not use this unless you have used the delegate option) #10.8.0.100 # Logging # Enable connection debugging facilities. # (see your syslog configuration for where pppd sends to) debug # Print out all the option values which have been set. # (often requested by mailing list to verify options) #dump # Miscellaneous # Create a UUCP-style lock file for the pseudo-tty to ensure exclusive # access. lock # Disable BSD-Compress compression nobsdcomp # Disable Van Jacobson compression # (needed on some networks with Windows 9x/ME/XP clients, see posting to # poptop-server on 14th April 2005 by Pawel Pokrywka and followups, # http://marc.theaimsgroup.com/?t=111343175400006&r=1&w=2 ) novj novjccomp # turn off logging to stderr, since this may be redirected to pptpd, # which may trigger a loopback nologfd # put plugins here # (putting them higher up may cause them to sent messages to the pty) cat /etc/ppp/options.pptp on Client1 and Client2 ############################################################################### # $Id: options.pptp,v 1.3 2006/03/26 23:11:05 quozl Exp $ # # Sample PPTP PPP options file /etc/ppp/options.pptp # Options used by PPP when a connection is made by a PPTP client. # This file can be referred to by an /etc/ppp/peers file for the tunnel. # Changes are effective on the next connection. See "man pppd". # # You are expected to change this file to suit your system. As # packaged, it requires PPP 2.4.2 or later from http://ppp.samba.org/ # and the kernel MPPE module available from the CVS repository also on # http://ppp.samba.org/, which is packaged for DKMS as kernel_ppp_mppe. ############################################################################### # Lock the port lock # Authentication # We don't need the tunnel server to authenticate itself noauth # We won't do PAP, EAP, CHAP, or MSCHAP, but we will accept MSCHAP-V2 # (you may need to remove these refusals if the server is not using MPPE) refuse-pap refuse-eap refuse-chap refuse-mschap # Compression # Turn off compression protocols we know won't be used nobsdcomp nodeflate # Encryption # (There have been multiple versions of PPP with encryption support, # choose which of the following sections you will use. Note that MPPE # requires the use of MSCHAP-V2 during authentication) # # Note that using PPTP with MPPE and MSCHAP-V2 should be considered # insecure: # http://marc.info/?l=pptpclient-devel&m=134372640219039&w=2 # https://github.com/moxie0/chapcrack/blob/master/README.md # http://technet.microsoft.com/en-us/security/advisory/2743314 # http://ppp.samba.org/ the PPP project version of PPP by Paul Mackarras # ppp-2.4.2 or later with MPPE only, kernel module ppp_mppe.o # If the kernel is booted in FIPS mode (fips=1), the ppp_mppe.ko module # is not allowed and PPTP-MPPE is not available. # {{{ # Require MPPE 128-bit encryption #require-mppe-128 # }}} # http://mppe-mppc.alphacron.de/ fork from PPP project by Jan Dubiec # ppp-2.4.2 or later with MPPE and MPPC, kernel module ppp_mppe_mppc.o # {{{ # Require MPPE 128-bit encryption #mppe required,stateless # }}} IPtables is stopped on clients and server, Also net.ipv4.ip_forward = 1 is enabled on PPTP Server. How can i solve this problem .?

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  • Same native and tagged vlan possible on Redhat?

    - by Chris Phillips
    Hi guys and gals, I'm looking at implementing a systems using a number of tagged and a native vlan connected to a server over a a/p bonded interface. The untagged vlan is for physical machine access, the tagged vlans are connected to bridges and then to QEMU VM's inside the machine. Hopefully this plan is fine, but I'm trying to implement a crippled version of this in a dev environment due to a lack of underlying network config in this location where I just have the same single vlan delivered to the machine on a tag AND plain. I'm nto clear if this is going to work (and that I should just be confident that it will work using different vlans) as I'm seeing odd things like a vm is arping out over the vlan out to the core switch, but the arp reply is coming back on the untagged interface. Now an ARP reply is unicast right? So it's a deliberate thing to send the ARP response on the untagged interface, and not a case that a broadcast response isn't being passed on the tagged side... i.e. there's some underlying logic pushing it that way. Something about the MACs somehow? This is on a CentOS 5.5 machine, vlan's from vconfig. (I've seen reference to the Linux mac-vlan project work, but that's not available here by default.) so 1) Should having the SAME vlan tagged and untagged work? 2) Will different tagged vlans to the untagged interface work nice and easily?

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  • How to force a host to not send a broadcast for an IP address in its own subnet?

    - by Bruce
    For a LAN, instead of a switch, I have built a topology where each machine is connected to a router. Each host is assigned an IP address from 10/8. Here are the interface details: Lets say I ping 10.16.0.3 from this host. The routing table of 10.16.0.2 has been configured to use the router (10.16.0.1) as the default gateway. But since the destination IP address (10.16.0.3) is in the same subnet it sends out an ARP broadcast. I want to disable this behavior of sending an ARP broadcast and instead force it to use the routing table. How do I accomplish this?

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  • Force netsh/arp binding multicast IP addres with specific MAC address

    - by Olivier
    I would like to setup an binding from an IP address to a MAC address using netsh. Goal is to bond an IP address which is a multicast address (224.224.x.y) to a given MAC address (which is NOT the calculated one from the multicast IP address : 01:00:5e:X:Y:Z It used to work with Windows XP (was it a bug that used to be "perfect" for my needs?), but Windows 7/8/8.1 forces the MAC address to the calculated one instead of letting me put what I want! (http://nettools.aqwnet.com/ipmaccalc/ipmaccalc.php shows MAC address calculation for multicast IP address) Thus I'm doing the following. Listing existing mappings: netsh.exe interface ip show neighbors "Ethernet" Interface 12 : Ethernet Internet address Physical address Type 224.0.0.22 01-00-5e-XX-YY-ZZ static Then adding my interface mapping manually: netsh.exe interface ip add neighbors "Ethernet" "224.xxx.yyy.zzz" "00-80-EE-UU-VV-WW" Finally, listing again my mappings: netsh.exe interface ip show neighbors "Ethernet" Interface 12 : Ethernet Internet address Physical address Type 224.0.0.22 01-00-5e-XX-YY-ZZ static **224.xxx.yyy.zzz 01-00-5e-UU-VV-WW static** As you can see, the MAC Address of the second entry (the one I just made) has been dynamically replaced by the calculated MAC Address corresponding to my IP Address... Calculation is done as follow (and displayed in hexa): UU=(xxx-128) VV=yyy WW=zzz But I don't want that behavior. My IP address and MAC address cannot be changed, and I must associate them accurately. Does anybody know how to disable MAC address substitution/calculation in netsh? Thanks, Olivier.

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  • VMware ARP/Mac Networking

    - by Ross Wilson
    Hi Guys, I am very interested in how VMware networking works. I have scoured the VMware website and read their data sheets, this has given me some basic knowledge. I now have some questions. Lets assume that we have a physical server running the VMware hypervisor. The physical server is running a Virtual Machine. The physical box has one physical NIC. The NIC is connected to a switch, as so is a desktop client. Now, this is where my first question lies. The VM has an IP address: 192.168.1.1. How do desktop clients on the network communicate with this VM? So, the client pings 192.168.1.1. The ping packet is sent to the switch. The switch checks its MAC address table and sees that 192.168.1.1 is associated with the MAC address of the physical NIC. Correct? I then assume that the ping packet is sent to the server's physical NIC, where the hypervisor routes the packet to the VM thats using 192.168.1.1? Please could you give me a run down as to how VM networking works? Many thanks, Ross

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  • DD-WRT router causing IP address conflicts across network

    - by r.tanner.f
    My DD-WRT router has lost its mind! I just set up two DD-WRT routers, one as a WAP (working fine) and one in Client Bridge (routed) mode (the problem). Not long after setup I started seeing IP address conflicts on other machines. The event log always points the finger at my Client Bridge router's MAC address. Neighbour table overflow The log on my router is flooded with Neighbour table overflow errors. These start a minute or two after boot. The network is rather large, with +200 IP addresses being used in this subnet. The other router shows no such errors. Mass ARP requests from 1.1.1.1 I'm also seeing constant ARP requests (with the problem router's MAC address) from 1.1.1.1. Seems like it's bugging everything on the network for its MAC address and then promptly forgetting it (or never receiving a response). Configuration: Model: Buffalo N600 Firmware: DD-WRT v24SP2-MULTI (03/21/11) Wireless Mode: Client Bridge (routed) I'm not sure what configuration details are relevant and I'd rather not have comments flooded, so just ping me in this chat if you want to know something. Why is my router stealing IP addresses and how can I stop it?

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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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  • How to configure remote access to multiple subnets behind a SonicWALL NSA 2400

    - by Kyle Noland
    I have a client that uses a SonicWALL NSA 2400 as their firewall. I need to setup a second LAN subnet for a handful of PC. Management has decided that there should be a second subnet even though intend to allow access across the two subnets - I know... I'm having trouble getting communication across the 2 subnets. I can ping each gateway, but I cannot ping or seem to route traffic fron subnet A to subnet B. Here is my current setup: X0 Interface: LAN zone with IP addres 192.168.1.1 X1 Interface: WAN zone with WAN IP address X2 Interface: LAN zone with IP address 192.168.75.1 I have configured ARP and routes for the secondar subnet (X2) according to this SonicWALL KB article: http://www.sonicwall.com/downloads/supporting_multiple_firewalled_subnets_on_sonicos_enhanced.pdf using "Example 1". At this point I don't minding if I have to throw the SonicWALL GVC software VPN client into the mix to make it work. It feel like I have an Access Rule issue, but for testing I made LAN LAN, WAN LAN and VPN LAN rules wide open with the same results.

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  • Db4o Mvc Application Architecture

    - by Mac
    I am currently testing out Db4o for an asp.net MVC 2 application idea but there are a few things I'm not quite sure on the best way to proceed. I want my application to use guessable routes rather than Id's for referencing my entities but I also think I need Id's of some sort for update scenarios. so for example I want /country/usa instead of /country/1 I may want to change the key name though (not perhaps on a country but on other entities) so am thinking I need an Id to use as the reference to retrieve the object prior to updating it's fields. From other comments it seems like the UUID is a bit long to be using and would prefer to use my own id's anyway for clean separation of concerns. Looking at both the KandaAlpha project I wasn't too keen on some aspects of the design and prefer something more along the lines of S#arp architecture where they use things like the [domainsignature] and EntityWithTypedId, IEntityDuplicateChecker, IHasAssignedId, BaseObject and IValidatable in their entities to control insert/update behaviour which seems cleaner and more extensible, covers validation and is encapsulated well within the core and base repository classes. So would a port of S#arp architecture to Db4o make sense of am I still thinking rmdbs in an oodb world? Also is there a best practice for managing indexes (including Unique ones as above) in Db4o? Should they be model metadata based and loaded using DI in a bootstrapper for example or should they be more loaded more like Automapper.CreateMap? Its a bit of a rambling question I know but any thoughts, ideas or suggested reading material is greatly appreciated. Thanks Mac

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  • NHibernate 2nd level cache provider for NHibernate 2.1.1.4000

    - by Rippo
    I am using s#arp which is built against NHibernate 2.1.1.4000, However I would like to use NHibernate.Caches.SysCache as my second level cache. However the Nhibernate contrib caches are built against NHibernate 2.1.2.4000 which obviously gives me a problem. Can anyone point me to a URL that I can download NHibernate.Caches.SysCache.dll that is built against NHibernate 2.1.1.4000 Or is there another 2nd level cache provider that is easy to implement and is built against NHibernate 2.1.1.4000 Thanks

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  • Update mysql database with arpwatch textfile database

    - by bVector
    I'm looking to keep arpwatch entries in a mysql database to crossreference with other information I'm storing based on mac addresses. I've manually imported the arpwatch database into my mysql database, but being a novice with databases I'm not sure what the best way to continually update the database with new entries without creating duplicates would be. None of the fields can be unique, as even the time is duplicated frequently. I'm not interested in the actual arpwatch events like flip flop or new station, just the mac/ip/time pairings. Would a simple bash (or sql) shell script do the trick? Would it be possible to make the mac address plus the time be a composite key of some sort? the database is called utility, table is arpwatch, columns are mac, ip, time a seperate table named 'hosts' with columns mac, ip, type, hostname, location, notes has mac as the primary key. This table will correlate different ip addresses that a mac had over time using the arpwatch column initial import was done with MySQL Workbench using INSERT INTO commands with creative search and replace on the text file

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  • Why would an iPod Touch and PS3 respond to netdiscover as 0.0.0.0?

    - by Iszi
    Only slightly related to this question, because it was discovered in the same scan: Can someone explain how this happened? When running netdiscover on my home network, my iPod Touch (identified by DHCP-reserved IP address and MAC address) responded to both its own IP address on our 10.x.x.x subnet and to 0.0.0.0 also. Why would this have happened? EDIT: After letting netdiscover run awhile longer, it seems one of the PS3s on the network is also answering to 0.0.0.0 - why is this?

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  • How to prevent response to who-has requests on virtual eth interface?

    - by user42881
    Hi, we use small embedded X86 linux servers equipped with a single physical ethernet port as a gateway for an IP video surveillance application. Each downstream IP cam is mapped to a separate virtual IP address like this: real eth0 IP address= 192.168.1.1, camera 1 (eth0:1) =192.168.1.61, camera 2 (eth0:2) =192.168.1.62, etc. etc. all on the same eth0 physical port. This approach works well, except that a specific third-party windows video recording application running on a separate PC on the same LAN, automatically pings the virtual IPs looking for unique who-has responses on system startup and, when it gets back the same eth0 MAC address for each virtual interface, freaks out and won't allow us to subsequently manually enter those addresses. The windows app doesn't mind, tho, if it receives no answer to the who-has ping. My question - how can we either (a) shut off the who-has responses just for the virtual eth0:x interfaces while keeping them for the primary physical eth0 port, or, in the alternative, spoof a valid but different MAC address for each virtual interface? Thanks!

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