Autologout of unused terminals

[Mike McNamara]

In article <213.nlunix6 at orcenl.uucp> bengsig at orcenl.uucp (Bjorn Engsig) writes:
>What I asked for in the first place was just a program to send SIGHUP to
>processes, which seemed to be doing nothing.  There will of course always
>be cases where this 'seems' is wrong, but a process that wants to live could
>easily do signal(SIGHUP,handler) (or nohup).  When doing this, you show that
>you are aware of the possible 'auto-killing', and you will be sure not to be
>killed.  This is also a nice thing to do on a modem line.

	Hmmm.  What is the phone number to your system?  You actually
ignore SIGHUP on dialup lines?  I'll just try your phone number every once
in a while (ok, I'll get a friend on the continent to try...) until I get in
just after you turn your home modem or terminal off without logging out.
	No need for a virus!  (It especially helps if you leave backgrounded
su shells... or games with high scores are good too!)

	Note: a good 15% of the bandwidth on the SYTEX network at
school went into programs the students wrote to echo ^@ at their 
terminals every 30 seconds so the SYTEX wouldn't drop their line.  
This wasn't due (only) to students wishing to hog terminal lines.

	The Unix systems hooked up to this terminal server ignored DTR.
In fact DTR was wired high on the back of the VAXen. (Or perhaps the DZ/DH
or what ever didn't do modem control.) Hence defeating the auto-disconnect 
`feature' of the terminal network was required to maintain the security 
of your account.  If the SYTEX dropped your line, Unix ignored (never saw)
HUP.  The next user, *ANYWHERE ON CAMPUS*, who connected to the same machine
via the switcher, got your existing login.  Pity the poor system manager, 
connected through the SYTEX, who pauses to answer a users question... 
*DISCONNECT*.  Across campus, the student's buddy, CONNECTS.  His terminal
prints

# 

Moral dilema.

Stupid site configuration.
(Of course the Unix admin's inherited the hardware with it's DTR ignorant
terminal multiplexors, and the guys in the IBM shop owned the SYTEX...)