When I installed and switched to 2.6.18 kernel from 2.6.32, I could no longer connect to the server. The reason for this is that apparently the network card signature changed with a different kernel version and the network card was renamed from eth0 to eth1 by a udev script and it was no longer part of vmbr0 bridge.
The way I fixed it is by removing the following two files from /etc/udev/rules.d/
70-persistent-net.rules
75-persistent-net-generator.rules
The way I fixed it is by removing the following two files from /etc/udev/rules.d/
70-persistent-net.rules
75-persistent-net-generator.rules