Xref: utzoo comp.unix.questions:5961 comp.unix.wizards:6870
Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!ll-xn!mit-eddie!minya!jc
From: jc@minya.UUCP (John Chambers)
Newsgroups: comp.unix.questions,comp.unix.wizards
Subject: Re: Usenet Security
Message-ID: <471@minya.UUCP>
Date: 5 Mar 88 04:42:12 GMT
References: <108@tron.UUCP> <2739@codas.att.com> <23504@hi.unm.edu> <3206@bloom-beacon.MIT.EDU>
Organization: home
Lines: 21
Summary: Feature, not bug...

In article <3206@bloom-beacon.MIT.EDU>, wolfgang@mgm.mit.edu (Wolfgang Rupprecht) writes:
> 
> Call-back is a great hack. Unfortunately it only works if the Unix
> system can insure that the phone connection is truly broken when Unix
> hangs up the modem. Some phone exchanges seem to have bugs that allow
> the call originator to keep the connetion open, even if the call
> recipient hangs up. 

Uh, this isn't always a bug.  I've worked in places that got sufficiently
many threatening phone calls that they got the phone company to arrange
for call termination only when the local end hung up.  That way, if you
got a weird call, you could leave the phone off the hook, and ask one of
the secretaries (via another phone line, usually) to trace the call.  One
place even had sets on the secretaries' desks that would show the number
of the calling party.  It was then easy enough to call the phone company
and ask for the physical location of that number, then call the police...

Of course, if you have this kind of service, then you can subvert the
call-back scheme exactly as Wolfgang describes.

-- 
John Chambers <{adelie,ima,maynard,mit-eddie}!minya!{jc,root}> (617/484-6393)