VirtualBox

Opened 2 years ago

Last modified 2 years ago

#20924 new defect

IPv6 not working out of the box with bridged WiFi and Linux guests

Reported by: treysis Owned by:
Component: network Version: VirtualBox 6.1.34
Keywords: IPv6 wifi bridge Cc:
Guest type: Linux Host type: Windows

Description

When using a bridge WiFi interface, IPv6 doesn't work out of the box on Linux guests. IPv6 becomes operational only after issuing "ip -6 neigh del <gateway-linklocal-ipv6> dev <dev>" as proposed in this gist: https://gist.github.com/0xquad/6090af4fe2c5b5fc6299 (although I found issuing it one single time suffices. No need to issue it repeatedly as the gist suggests).

This problem occurs only with Linux guests. Windows (10?) guests can use IPv6 just fine without any additional steps. Several WiFi NICs (Intel, Realtek) were tested, as well as several routers (FritzBox, Compal, generic OpenWrt). Confirmed also by different people, with different distros, including at least Ubuntu 20.04, 21.10, 22.04, Linux Mint 19.x, Mint 20.x, ArchLinux, Kali 2021. I don't have a Linux host to test with, but it's at least a bug with Windows hosts.

The bug appears similar to https://www.virtualbox.org/ticket/5503 (supposedly fixed) and https://www.virtualbox.org/ticket/14212. However, the latter mentions broken promiscuous mode as problematic. Since Windows guests aren't affected, I think that this is a different bug. The bug exists at least since VirtualBox 5.x, probably earlier versions affected as well.

Change History (6)

comment:1 by treysis, 2 years ago

The bug only occurs on bridged WiFi. Bridged ethernet works fine with both Windows and Linux guests.

comment:2 by treysis, 2 years ago

IPv6 connectivity also becomes functional after pinging the gateway's Global Unique Address (GUA), which is successful, and after which global IPv6 connectivity starts to work.

comment:3 by treysis, 2 years ago

Some more info: this also affects Windows guests.

Without IPv6 activity, IPv6 connectivity will cease to work after a couple of minutes. This happens on both Linux and Windows guests. On Linux, IPv6 connectivity can be restored by reissuing the command mentioned in the ticket. On Windows, it can be restored by disconnecting and reconnecting the network adapter in VBox's network control.

comment:4 by pm4492, 2 years ago

My env is this

  vb7.0
  windows host
  linux guest
  bridged WiFi

The problem I see is that my host and guest present the same mac to outside, and vb is able to forward ipv4 packets correctly intended for guest but fails for ipv6 packets.

comment:5 by pm4492, 2 years ago

Found two really useful posts about bridged WiFi. Perhaps ipv6 frames are not properly intercepted and forwarded to guest by VBOX.

https://forums.virtualbox.org/viewtopic.php?f=35&t=96608#p468775 https://forums.virtualbox.org/viewtopic.php?f=6&t=84831#p473039

comment:6 by pm4492, 2 years ago

Never mind. Deleting the neighbor once does work.

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