Quirky VirtualBox/Networking Question

undomiel

As always under a time crunch so I didn't get to investigate this situation properly. Hopefully later on I will be able to dig in. Anyhow this will expose my weakness in networking knowledge so don't laugh at me too hard!

The client wanted a p2v done of their ancient win2k server, on to their only aged win2k3 server. We opted for virtualbox since that is what I'm the most comfortable with. After this experience though I'm much less likely to recommend it as being production ready, since having consoles open under multiple accounts will result in the config being overwritten by the last console closed. Anyhow after loading up the vm and getting everything configured using bridged networking we tested it out and everything worked out over the network. We gave the host a reboot and then loaded up the vm again just to demonstrate a bit more. Much to my surprise the networking was completely failing. Couldn't connect anywhere and couldn't ping out anywhere. That was rather embarrassing. For future notes, need to test before and after rebooting the host instead of expecting everything to work properly.

After a bit of troubleshooting I found that the guest could ping the host, but nothing else. Sometimes if you switched to NAT it would work fine, but generally that was broken too. Definitely wouldn't work after rebooting the guest. Out of curiosity I was wondering if virtualbox was sending out the packets to the switch or not, so I disconnected the network cable and tested. Sure enough now I couldn't ping the host. After reconnecting the cable came the surprise though. Now I could ping everywhere internally and over the internet. Consistently too as I still could several reboots later. Tested rebooting the host and the problem resumed. Disconnected and reconnected the cable and the problem went away. So now I have the client doing that whenever they need to bring up this vm. I didn't get a chance to install a packet sniffer so I didn't get to see what was going on at that level. My question is, does anyone have an ideas as to why this would be happening? It has me a bit confused. If it matters or not the switch is a 3550. Hopefully at some point I will get a chance to investigate some more.