TCP/IP Communications Problem

[Bruce Hudson]

<>
  I am having problems with the `talk' program in attempting to talk between
two users on different machines. The two machines both run 4.2BSD and are
connected using an itt network.

Esentially, the problem is this: On machine A, user1 types

	`talk user2 at machine-B'

The first thing that talk does is send a message to machine B to see if user2
is already trying to talk to user1 at machine-A. Unforunately, the answer never
comes back. At this point, talk goes into an infinite loop - periodicly
re-sending the request message.

After much looking {a wizard I am not!}, the problem was tracked down to
differing hosts files on the two machines. These are --

A:hosts		127.1	machine-A	localhost
		126.1	machine-A-net
		126.2	machine-B-net	machine-B

B:hosts		127.1	machine-B	localhost
		126.1	machine-A-net	machine-A
		126.2	machine-B-net

What happens is that talk builds into the message his return address. To do
this he looks up his machine name in the hosts file and uses the address
returned - 127.1. Of course, when the talk daemon on machine B tries to 
respond to 127.1, the answer goes nowhere.

I have tried a number of solutions. The names of the respective machines
apparently have to stay at 127.1 or even local talks fail. Apparently, itt
does not know how to talk locally. Someone locally who does not run BSD Unix
suggested that the problem lay in the gateways files which are currently
empty on both machines. However, every combination that I could think of 
failed to do any good - some did harm.

Any help would be gratefully appreciated. I have run out of ideas to try. If
you want more information, just ask.

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Bruce Hudson				{dartvax|utcsrgv}!dalcs
Dalhousie University