Re: Bridge interface and IP address

[Michael Richardson <mcr%sandelman.ca@localhost>]

>>>>> "Manuel" == Manuel Bouyer <bouyer%antioche.eu.org@localhost> writes:
    >> I'm looking for the answer for a question, if it is allowed
    >> somehow to assign an IP address to the virtual bridge interface ? 
    >> As far as i know it is possible in Linux. I believe it can also
    >> be done in FreeBSD using just ifconfig. It seems impossible in
    >> NetBSD. I could not find any information about that, and man page
    >> does not specify it either. Thanks in advance for your response.

    Manuel> No, you can't assign an IP address to a bridge in NetBSD.
    Manuel> Just assign the IP to one of the interfaces member of the
    Manuel> bridge, it will have the same effect as assigning the IP to
    Manuel> the bridge itself on linux.

Or, to put it another way, Linux has to assign the IP to the bridge
device because the bridge code hijacks the normal packet processing from
the (physical) interface, so packets can never get in via the physical
interface.   But, if the interface has an IP, then the routing code is
confused for outgoing packets, and basically nothing works.

This is often pathological for IPv6 on Linux, because the interface will
autoconfigure based upon RAs, and thus you are hosed without even
starting.  Turning off ra_accept is hard on a lot of systems, because
there is no ra_accept until the ipv6 module loads, at which point it's
too late to turn it off if your interfaces are already "up".

-- 
]       He who is tired of Weird Al is tired of life!           |  firewalls  [
]   Michael Richardson, Sandelman Software Works, Ottawa, ON    |net architect[
] mcr%sandelman.ottawa.on.ca@localhost http://www.sandelman.ottawa.on.ca/ 
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