I consider myself fairly avid with Ubuntu and Linux, but this one has me stumped. I built up a Xen Server using Ubuntu 12.04 as the base operating system. It has multiple domUs running on it. My home network has a statically defined network where I got all the network connectivity going peachy. The server was moved to a permanent home this morning. So, the network configuration on the main system had to change. Again, another static network, but now I can't ping the upstream gateway from the host. As the VMs use this NIC over a bridge, they too are broken. Ping responds with "destination host unreachable." I simplified the networking down to a simple static network as seen below (no bridge or anything) just to get it to work.
Here's the contents of my /etc/network/interfaces file:
auto lo iface lo inet loopback auto eth0 iface eth0 inet static address 126.96.36.199 gateway 188.8.131.52 netmask 255.255.255.240 broadcast 184.108.40.206 network 220.127.116.11 dns-nameservers 18.104.22.168 22.214.171.124
Here's the contents of route -n
0.0.0.0 126.96.36.199 0.0.0.0 UG 100 0 0 eth0 188.8.131.52 0.0.0.0 255.255.255.240 U 0 0 0 eth0
And the results of pinging the gateway:
PING 184.108.40.206 (220.127.116.11) 56(84) bytes of data. From 18.104.22.168 icmp_seq=1 Destination Host Unreachable From 22.214.171.124 icmp_seq=1 Destination Host Unreachable From 126.96.36.199 icmp_seq=1 Destination Host Unreachable
Again, this worked in one network flawlessly (obviously with different parameters in the interfaces file). I did try using eth1 (as there are two NICS on the server (in case the MAC address got flipped on bootup). No success there. Yes, the cable is in the right port now :)
I appreciate the help!
Further investigation resulted in finding out the following characteristics. Grub gives you two main boot options after xen is installed. One for the vanilla kernel without Xen, and one with Xen. The default is to use the Xen boot configuration. If I use the vanilla kernel option, with no Xen, networking is just fine. If I use the Xen option, networking breaks. I compared the routing tables for the two setups with "route -n" and they are identical. The /etc/network/interfaces file hasn't changed. So, it must be something to do with the way the bridge is setup, or Xen performs it's network initialization. This is diving into an area I'm unfamiliar with. Can anyone give me an idea how to proceed solving this problem? Otherwise, I have to bail on Xen (which I don't want to do) and try VirtualBox instead. This is horribly frustrating.