virtualbox.org

I know how strange the topic sounds, but it’s the best way I can describe it. I’m on a Centos 6 host. I use a 1-month old version of VB. I’m running in Bridged Adapter mode. I run 2 guests with world reachable static IP’s. All was going perfectly well until a few days ago.

When I run a trace route on guest 2, BOTH guest IP’s are showing up in the route. More specifically…

When I trace route guest 2… The IP for guest 1 is showing up as the second last hop. In other words, requests to guest 2 appear to be looping through guest 1 somehow. It’s like guest 1 is inserting its IP into the guest 2 route.

Am I making any sense here? I’ve googled and googled and googled…. I’ve messed with every possible part of the configuration. Yes, I can stop the guest 1 IP from showing up in the guest 2 trace route if I shut it down. I could babble on here with all sorts of additional information, but I’ll leave it here for now.

Can anyone give me a hint of where or what I should be looking for in order to solve this? Hoping it’s something simple.

Solved

Well sort of. I had packet forwarding enabled for OpenVpn… net.ipv4.ip_forward = 1 If you do this on a VirtualBox guest, or at least the first guest, you end up with duplicate packets, or packets being forwarded to the next VM in line. I’m not sure if this is a bug, or if it’s something you just can’t do when you’re using Bridged Adapter Mode. In any event, I’ve solved the issue for now.