I have a debian vm with one IP address and hostname A.
I changed the /etc/network/interfaces to another IP and added 2 more eth0:1 etc. I changed the hostname to hostname B in /etc/hostname and rebooted the vm.
After reboot, I can ssh into the vm from dom0 and I can ping dom0 from the vm. However I can not ping past dom0 and I can not ping the vm from another physical machine. /xen/vm.cfg is wrong and so is /etc/webmin/servers/12335.serv but fixing it doesn't make the problem go away even after vm is rebooted.
Rebooted dom0 and same problem.
Changed IPs again to three other IPs in /etc/network/interfaces as well as hostname to hostname C. Rebooted VM and everything works. /xen/vm.cfg is wrong and so is /etc/webmin/servers/12335.serv
Changed back to hostname B and previous 3 IPs. Everything works after vm reboot. /xen/vm.cfg are wrong and so is /etc/webmin/servers/12335.serv
Does anyone have an idea what might block routing from dom0 out or in? I checked IPtables in all cases but fixing the entries in it didn't help. Route also appeared to be correct.
Is there a bridge configuration somewhere that I am missing?
What would be the ideal way to change IPs on a vm managed by cloudmin? Only ssh is running on the vm.
Comments
Submitted by JamieCameron on Thu, 10/14/2010 - 13:52 Comment #1
Could be a routing issue - was the IP that is not working on a different subnet to the original? If so, you'd need to change the gateway in /etc/network/interfaces as well, and then reboot the VM.
Submitted by cobolt on Thu, 10/14/2010 - 14:58 Comment #2
The IPs are all on the same subnet. Odd thing is non of the 3 IPs assigned worked. I could only ping dom0.
Submitted by JamieCameron on Thu, 10/14/2010 - 15:05 Comment #3
Are all the IPs routed to your dom0 machine by your ISP?
Also, are the IPs on the same subnet as the dom0's eth0 address?
Submitted by cobolt on Thu, 10/14/2010 - 19:57 Comment #4
I was able to find the problem.
The firewall/router for the subnet was responding to ARP requests which it cached. That IP belonged to another machine with a different mac address before I used it on this vm.
Flushing the arp cache fixed it.