Re: CURRENT: can not add device to bridge: ifconfig: BRDGADD igb0: Invalid argument

Am Tage des Herren Mon, 19 May 2025 11:22:31 +0200
"Patrick M. Hausen" <pmh@hausen.com> schrieb:

> Hi all,
> 
> > Am 19.05.2025 um 10:53 schrieb Lexi Winter <ivy@FreeBSD.org>:
> > 
> > the basic problem here is that putting IP addresses on a bridge member
> > is a layering violation and it's just not reasonable (or even possible)
> > to support this in a sensible way in bridge.  this is why most dedicated
> > network devices (switches, routers, etc.) don't let you do this.  
> 
> Adding to this, the fact that IP addresses on member interfaces are not
> supported has been documented from day one of the introduction of if_bridge(4).

So the concept is to have if_bridge() facing "towards the network", with IPv4 and/or IPv6.

My "concept" - or better "minded topology" - on how to connect computers is probably outdated
or mislead, sorry for the noise.

On the host in question I was able to switch towards the correct concept without consulting
the aformentioned sysctl. bridge0 has a internal IPv4, IPv6 ULA, has a physical NIC (igb0) as
member and a bunch of epair() vnet interfaces.

I need a IPv6 prefix on bridge0. With the "wrong/faulty" concept I simply used 

rtsold_flags="-iu igb0"

within /etc/rc.conf. Changing this line to
rtsold_flags="-iu bridge0" while bridge0 is up and running doesn't work, neither does "rtsol
bridge0" show any results.

Is there any othe MIB OID for if_bridge() to be aware of to achieve the desired behaviour?

Kind regards,
Oliver

> 
> A couple of months ago I did check the commit times of the code and the
> relevant handbook section because exactly this discussion came up again
> in a different context.
> 
> https://docs.freebsd.org/en/books/handbook/advanced-networking/#network-bridging
> 
> > If the bridge host needs an IP address, set it on the bridge interface, not on the member
> > interfaces  
> 
> Kind regards,
> Patrick



-- 

A FreeBSD user