Guests on Linux host have flaky network access when bridged across wireless

[spiffytech]

Across two computers, across a couple of Linux distros (Fedora and openSUSE), across Windows and Linux guests, across 6 months:

When I set a VM to use bridged networking to my wifi card, the guest has spotty access to the Internet. Other computers on the LAN can talk to the guest just fine, but if the guest tries to talk to anything on the Internet 9 times out of 10 it'll get some variant of "connection reset".

This only occurs when bridged to my wireless card (I've tried on different networks, and it's the same)- bridging to my Ethernet card causes no problems.

[bujon]

I have the same problem. Host CentOS 6.3 with virtualbox 4.2.12, guest CentOS 5.9 bridged to wireless network adapter. When bridged to etherenet works fine. On win Vista host everything works fine too.

[Valery Ushakov]

This might be fixed in 4.3.16.

WiFi routers try to send multicast ethernet frames as unicast if possible and these packets were not delivered to the guest correctly. #10019 has some more details on this.

In particular, ARP requests from the WiFi router are affected by this problem - though the router eventually gives up and send ARP as real broadcast and gets back the reply restoring connectivity until the next expiration of ARP cache entry for the guest.

[Valery Ushakov]

Please, reopen with packet traces if there are still problems.