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From: steve@tove.UUCP (Steve D. Miller)
Newsgroups: net.lan,net.unix,net.unix-wizards
Subject: Re: Re: remote logins not showing up in 'w' command
Message-ID: <243@tove.UUCP>
Date: Wed, 19-Jun-85 14:47:11 EDT
Article-I.D.: tove.243
Posted: Wed Jun 19 14:47:11 1985
Date-Received: Sun, 23-Jun-85 01:25:43 EDT
References: <557@bgsuvax.UUCP> <205@ubvax.UUCP>
Organization: U of Maryland, Laboratory for Parallel Computation, C.P., MD
Lines: 39
Xref: watmath net.lan:880 net.unix:4850 net.unix-wizards:13590

> Although I am not a rlogin user ... I have gotten the impression
> that rlogin is handled through the uucp login.  Thus, your "rlogin"s
> would appear to be "uucp" logins that are running "uuxqt".
> 
> I think this is supported by the fact that "rlogin" doesn't require a
> password.  If "login" was being used, you would see the user in a "w",
> but you would have to give a password.

Wrong.  Rlogin works using 4.2 IPC; there is a rlogin daemon that lurks
out on some port or another (it's listed in /etc/services) and accepts
connections from other machines.  Some strange authentication protocol
is followed (see the manual entry for rshd), and eventually a login process
gets exec()ed off with the "-r" (use remote protocol) flag.  Login then
reads an environment variable or two (probably just your TERM, but maybe
some other stuff; I'm speaking off the top of my head here, in case you
all hadn't yet noticed), and runs just like it would anywhere else.

   Part of the aforementioned authentication protocol includes a check
of the .rhosts file (if any) in the user's remote directory and, if
necessary, a check of /etc/hosts.equiv to see if the user is "priviledged".
If so, he or she is not asked for a password; if their name (i.e. 
"gyre.arpa steve") is not in their .rhosts, or if their machine (i.e.
"gyre.arpa") is not listed in /etc/hosts.equiv, they get asked for
a password.

   I haven't been following much of the discussion that the original
article started, but I do remember seeing a whole list of things
dealing with pseudo-ttys that sounded like they might well be at
the heart of the problem.  I feel that everyone running 4.2 should
have some pseudo-ttys out there in /dev; there are programs that
never touch the net -- like emacs -- that use them, and strange
things happen when they aren't present.

   Ain't networking grand?!?

-- 
Spoken: Steve Miller 	ARPA:	steve@maryland	Phone: +1-301-454-4251
CSNet:	steve@umcp-cs 	UUCP:	{seismo,allegra}!umcp-cs!steve
USPS: Computer Science Dept., University of Maryland, College Park, MD 20742