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Date:      Mon, 7 Aug 1995 08:00:35 +0200 (MET DST)
From:      J Wunsch <j@uriah.heep.sax.de>
To:        freebsd-current@FreeBSD.org
Subject:   Re: workaround for talk's address problem
Message-ID:  <199508070600.IAA01971@uriah.heep.sax.de>
In-Reply-To: <199508070036.RAA04944@gndrsh.aac.dev.com> from "Rodney W. Grimes" at Aug 6, 95 05:36:55 pm

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As Rodney W. Grimes wrote:
> 
> The correct fix here is to do what ftp, telnet or any other TCP cleint
> does, go to the next address if an error or timout occurs on the current
> address.  When we get to the end of the list of addresses, then exit
> the program with an error.
> 
> Adding options to force a negotiation address is not going to make
> the users happy, but the above surely well.

But the timeouts will be enormous, i don't believe this would make
people happy either. :-(

Remember, talk is using UDP, you cannot see if a ``connection'' has
been established unless somebody has been answering.  Perhaps you
could ``multicast'' the requests with all known addresses and see
where you got a response, but...

I think most people here didn't really understand talk's special
problem: the talk protocol uses a caller-provided addresses to respond
to, even though the callee should better use the address as he's got
it out of the IP header.  My suggested change does only affect this
address.

Casting connection requests with various addresses around is IMO not a
Good Thing.  It will cause bogus (internal) addresses to be spread
around that should never see the outside world (like 192.168.x.x in my
example).

I think the major problem is in the talk protocol and its actual
implementation, but this doesn't help us very much since we cannot
convert every talk daemon on the world.  FWIW, the ytalk package does
provide a very similar scenario (even though i didn't understand its
usage yet :).

-- 
cheers, J"org

joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/
Never trust an operating system you don't have sources for. ;-)



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