On Tue, Aug 19, 2003 at 06:41:03PM +0000, Michael van Elst wrote:
> [...]
> N.B. I'm not sure if an 'ifconfig down' actually has to terminate
> connections. We were talking about the case where the socket address
> becomes invalid. That's not an arbitrary 'ifconfig down' or address
> change but a system-wide condition saying that there is no interface
> that could possibly send from the previous address.

*right now* there isn't one, but there may be one again in the near future.
Also, note that new connections attemps will be rejected with "can't assign
requested address".

TCP hides networks details to the applications. Once the connection
is established, it expects the stack to deliver it to the remote end
within a specifed amount of time, or get an error once this amount
of time has expired. The application doesn't care if we swapped an interface
in the meantime, or if the address was deleted and added back.

So yes, when an address change or an interface goes away we can't
terminate existing connections, because it may eventually come back in
some time.

-- 
Manuel Bouyer <bouyer@antioche.eu.org>
     NetBSD: 24 ans d'experience feront toujours la difference
--