Network timeouts

[Jon Schewe]

I'm using virtualbox 3.2.8 on Mac OS Snow Leopard. I have 2 NetBSD virtual machines that have 3 network cards: 1) NAT 2) host only to do NFS to host 3) internal network to do network testing

When I leave the machines idle for some time, half hour to an hour, and then come back to them, the host only network dies. They can ping each other through the internal network and they can ping the outside world through the nat, however they are unable to ping the host through the host only and the host cannot ping the guests through the host only network. Watching tcpdump on the guests, I see traffic going out, but nothing coming in. If I keep a ping going continuously I find that I will get request timeouts for 50 or so messages and then they'll all come in at the same time.

Right now the workaround is to suspend the guest(s) and then start them again, then everything is fine.

[Jon Schewe]

One other thing to note, I am running the 64-bit kernel by passing arch=x86_64 to the kernel at boot time.

[Frank Mehnert]

Just to be sure: Did you choose the same virtual network device type (pcnet or e1000?) for all three network cards?

[Jon Schewe]

Yes they are all pcnet cards.

[Jon Schewe]

I switched back to the standard 32-bit kernel and I just had another lockup right now. The guest with the problem could ping another guest on the internal network, but could not ping the host on the host-only network. Nor could it ping the other guest on the host-only network. The problem guest can still ping the outside through the NAT interface.

[David Chisnall]

I see similar behaviour with FreeBSD VMs on OS X. This isn't new - it's happened on 10.5 with VirtualBox 2.x right up until the latest version. My VM has a host-only network and a bridged network. Both exhibit the same kind of symptoms, but the host-only one seems a lot more fragile.

Sometimes trying to renew the DHCP lease in the VM will make the network start working, but not always. dhclient in the VM can usually (always?) talk to the DHCP server, but not to the host, which makes me suspect that the problem is in the vboxnet kernel module. Unloading and then reloading this module seems to make things work again in the cases where the network won't work even after restarting the VM.

[Jon Schewe]

I'm finding that it's worse when my Mac host is under high load.