Re: if_bridge(): IPv6 EUI-64 seemingly not working

Am Tage des Herren Tue, 17 Jun 2025 15:52:34 +0100
Lexi Winter <[email protected]> schrieb:

> FreeBSD User:
> > net.link.bridge.inherit_mac: 1
> > [...]
> > 
> >         ether 4c:52:62:2b:05:eb
> >         inet6 fe80::5a9c:fcff:fe00:393a%bridge0 prefixlen 64 scopeid 0x6  
> 
> i was able to reproduce this:

First of all, thank you very much for checking this.

> 
> # sysctl net.link.bridge.inherit_mac=1
> net.link.bridge.inherit_mac: 0 -> 1
> # ifconfig bridge1 create inet6 -ifdisabled auto_linklocal up
> # ifconfig bridge1 | egrep 'ether|inet6'
> 	ether 58:9c:fc:10:43:03
> 	inet6 fe80::5a9c:fcff:fe10:4303%bridge1 prefixlen 64 scopeid 0xa
> # ifconfig epair create
> epair2a
> # ifconfig bridge1 addm epair2a
> # ifconfig bridge1 | egrep 'ether|inet6'
> 	ether 02:36:0f:34:6b:0a
> 	inet6 fe80::5a9c:fcff:fe10:4303%bridge1 prefixlen 64 scopeid 0xa
> 
> some observations:
> 
> - i don't think this is caused directly by the member_ifaddrs changes.
> 
> - you can work around the problem by manually setting the bridge link
>   address when creating it instead of using inherit_mac, i.e.:
> 	  ifconfig bridge1 create link 02:00:00:00:00:01
> 
> - i don't think this is a bug per se, it's more that we simply don't
>   update the IPv6 lladdr when an interface's MAC address changes.
>   but i've copied net@ in case anyone else has an opinion on this.

I'd dare to disaggree, we have running several recent CURRENT and 14-STABLE boxes (almost
every 2nd day recompiled world/kernel) with very close configuration schemes (according to
kernel config and NIC/bridge config as far it is possible to say so with respect to the
different OS and different network addresses). On 14-STABLE with very similar jail
configuration I do NOT see this (mis)behaviour of if_bridge(). 


-- 

A FreeBSD user

-----BEGIN PGP SIGNATURE-----

iHUEARYKAB0WIQRQheDybVktG5eW/1Kxzvs8OqokrwUCaFGejgAKCRCxzvs8Oqok
rxQKAP4wu3mzc457wP1gM3wreYHJukfO0vQmIYu6aOG+aoGi0AEA/DuqcI1JeOMf
WF6OYthKizsfniNAwd/lLahbg/75EwY=
=6Xx8
-----END PGP SIGNATURE-----