Talk and \"protocol not supported\"

[abdullah]

 Tom Perrine writes:
>Our current head scratcher involves "talk" and some other similiar
>programs.  When I try to talk to someone I get the screen cleared and
>then a message "Bad Socket (43)" or somesuch.  When I looked this up in
>intro(2), I discovered that 43 is "Protocol not supported".  The system
>where this occurs is not on a network, although we have been playing
>with the config file, trying to get this to work.

     I would speculate that the problem is with /etc/hosts rather than
with the configuration file. The reason is that we had similar problems
with our 780 running 4.2 (not on any network). The light dawned on me
when I read an article by Fred Avolio (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 it's /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). You
should edit your /etc/hosts to put in localhost ; kill  your current
talk daemon and restart it. Hopefully it will work. Here is our
/etc/hosts:

#
# Host Database
#
127.0.0.1	nucsrl localhost

     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)

			      Naim Abdullah
			      Dept. of EECS,
			      Northwestern University
			      ihnp4!nucsrl!naim