Talk and \"protocol not supported\"

[Chris Torek]

>Tom Perrine writes:
>>Our current head scratcher involves "talk" and some other similiar
>>programs. ...
>
In article <2410001 at nucsrl.UUCP> naim at nucsrl.UUCP (abdullah) writes:
>I would speculate that the problem is with /etc/hosts rather than
>with the configuration file. ... I read an article by Fred Avolio

[Look, Fred, someone finally spelled your name right! :-)]

>(ihnp4!decuac!avolio) in net.bugs.4bsd regarding a problem with
>syslog running on a machine not on a network.
>     Such a machine HAS to have the word "localhost" in its /etc/hosts
>entry. The address does not matter (although 0 is probably not a good
>idea since it is used for something special; I forget what).

However, it should always be 127.0.0.1, lest `martian datagrams'
leak out later.  You must also be sure to `ifconfig lo0 localhost up'
in /etc/rc or /etc/rc.local.

Alas, I do not believe that this is related to the talk bug; syslog
and talk were both new in 4.2BSD, and the author(s) of talk most
likely did not know about syslog.  (Indeed, I believe that only
sendmail knew of syslog in 4.2BSD.)  All of this is quite different
in 4.3 (and possibly in Ultrix 1.2 as well).

>     Can some guru explain where in the *source* is the presence of
>localhost checked for? Is it in the network library routines or
>where? (certainly not in the source for talk)

The syslog routines open an AF_INET connection to `localhost's
syslog port.  If you have no `localhost' entry, the 4.2BSD syslog
that is part of sendmail opens the console instead, then prints a
bogus message about not being able to open /dev/console.  (As I
recall, there were two `syslog's on our 4.2 tapes; at most one
of them---the one in sendmail's aux directory---worked at all.)
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 1516)
UUCP:	seismo!umcp-cs!chris
CSNet:	chris at umcp-cs		ARPA:	chris at mimsy.umd.edu