Linux bridging not forwarding packets

Solution 1:

It's possible that the underlying network devices on the host do not have promiscuous mode enabled. In VMWare, for example, if the underlying virtual network adapter isn't +promisc then the guest bridge will fail miserably -- even though it thinks its able to enter promiscuous mode, it can't.

I've never used HyperV, but the logic should be the same, if the host doesn't allow the guest to enter promiscuous mode, the bridge can't pass packets back and forth because the network card will only handle frames that are addressed specifically to it.

If you disable the bridge, you're able to ping NUX3 and the router, correct?

Solution 2:

in the hyper-v manager, go to the settings for the vm you want to use a bridge on, and under every network interface that you want to use as part of the bridge enable the "allow mac address spoofing" checkbox. I'm using Windows Server 2008r2 SP1. That's what I did to get it to work. I'm also using Ubuntu 12.04 which has all the Hyper-V drivers preinstalled, but I don't think that matters.

Solution 3:

Bridging works fine.

  1. As saying before need to enable MAC address spoofing
  2. In latest kernels iptables rules actuals for bridge too. So it must configured or disabled. For disable iptables rules for bridges execute: sysctl net.bridge.bridge-nf-call-iptables=0