On Sun, Jul 28, 2013 at 4:46 PM, Paul Gray <[email protected]> wrote: > > On Sat, Jul 27, 2013 at 4:45 PM, Muhammad Yousuf Khan > > <[email protected] <mailto:[email protected]>> wrote: > > > this is not happening very frequently . but happen once in a > > 3 month and not on all machines but few machines. > > > > the problem is, VM stop reaching the LAN and WAN. > > > > when i ping , it says "destination host unreachable" > > If you've verified the machine is up and ruled out any possible cabling > issue, then I'd recommend the following to troubleshoot this further: > > *) Verify that the MAC assigned for the VM is unique. This really > shouldn't be the issue, but you didn't state how the VMs were created > nor whether this issue was aligned with VMs with certain > characteristics. So I mention this just because it'd be one of the > first things I'd check if I was manually scripting the creation of a the > VMs. > > i use mostly command line to create VM, and there could not be an issue in MAC address since i bind the back with VM ID and VM ID is always unique. my binding i means i use VM ID in mack addresses. so i am very vigilant when i am creating LAN Cards
> You also didn't mention if this was across all OS'es in your system, or > one particular OS. I'll assume that your issue is with Linux VMs, and > if that's not the case, then read on for your enjoyment knowing that the > same approach to troubleshooting works for other OS's as well. > > no i clearly mention that it is "windows 7", and no, i never observe such thing happening in Linux machine. i do not use openvz, instead only KVM. and never found anything like this happening in debian. > *) Check ifconfig on the host - does it show the state of the interface > as UP? Are there errors? For example: > > gray@debian:~$ /sbin/ifconfig eth0 > eth0 Link encap:Ethernet HWaddr 00:aa:00:ae:5d:d0 > inet addr:192.168.10.211 Bcast:192.168.10.255 > Mask:255.255.255.0 > inet6 addr: fe80::2aa:00ff:feae:5dd0/64 Scope:Link > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 > RX packets:260024861 errors:0 dropped:0 overruns:0 frame:0 > TX packets:139022869 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:1000 > RX bytes:294358199688 (274.1 GiB) TX bytes:429610650518 > (400.1 GiB) > Interrupt:23 Base address:0x2000 > > Note on the 3rd line, the interface is listed as "UP". > Note on the 4th and 5th lines, there have been no receive or > transmission errors. > bytheway, i will definitly try to check this next time on OS guest virtual network adapters bind to the VMs > > If the interface is not up or there are errors, check the logs on the > host for possible causes. > > nope it is up and showing limited connectivity "!" mark > Check the same fields on the tap/bridge interface on the Proxmox hosts > as well. (Are the hosts with problems connected to the bridge or NAT'd? > or a mix of both?) > > yes, as i said i will try suggested next time when it happens. > *) If the interfaces are all up and no errors reported, ping from and to > the host again (which is going to fail...yes). Immediate afterward, > check the arp tables on both the host and the proxmox server to see if > the arp tables are correct. Check "/usr/sbin/arp -n". Is the target > MAC listed as (incomplete)? > > ok, thanks for the tip > *) Fire up tcpdump and watch for ARP negotiation and subsequent ICMP > packets working their way across the network. Where does the paradigm > start to fail? > ok! > > *) Anything such as iptable scripts, fail2ban or portsentry in place > that would be intercepting traffic? > > nope, my OS is clean from all of that because they are already behind a firewall so no need for iptable > If none of the above apply, please provide more specifics on your > implementation: The OS's involved, the .conf file for the VM, etc. > ok i will do that, Thanks > -- > Paul Gray -o) > 314 East Gym, Dept. of Computer Science /\\ > University of Northern Iowa _\_V > Message void if penguin violated ... Don't mess with the penguin > No one says, "Hey, I can't read that ASCII attachment ya sent me." > _______________________________________________ > pve-user mailing list > [email protected] > http://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-user >
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