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From: dudek@endor.UUCP
Newsgroups: comp.mail.uucp
Subject: Re: Too many hops... Why?
Message-ID: <1138@husc6.UUCP>
Date: Fri, 30-Jan-87 21:23:31 EST
Article-I.D.: husc6.1138
Posted: Fri Jan 30 21:23:31 1987
Date-Received: Sat, 31-Jan-87 08:59:53 EST
References: <103800001@datacube> <103800002@datacube>
Sender: news@husc6.UUCP
Reply-To: dudek@harvard.UUCP (Glen Dudek)
Organization: Aiken Computation Lab Harvard, Cambridge, MA
Lines: 32

Ahhh, that last bounce: 'ocean.harvard.edu - I refuse to talk to
myself' was due to one of my sendmail configuration files which
failed to function correctly when said site ('ocean.harvard.edu')
upgraded to 4.3BSD.  My fault, sorry.

What follows is a complaint about 4.3BSD sendmail and domain servers -
those of you lucky enough not to have either can ignore this...

What actually caused the problem was a 4.3BSD version of sendmail which
supports the domain servers, and sets the '$w' (hostname) macro to
'ocean.harvard.edu', instead of just 'ocean'.  My sendmail.cf tried to match
mail addressed to 'user@ocean' by using the '$w' macro, which of course
failed.  The sendmail.cf then decided that this was non-local mail, which
it should deliver to that other host 'ocean', which it tried
to do.  Sendmail cleverly realized that it was talking to itself, and
bounced the message with the 'I refuse to talk to myself' error, thus saving
a costly mail loop (and also avoiding the 'too many hops' problem).

The fix was to hardwire the hostname 'ocean' in the sendmail configuration
instead of using the '$w' macro.  This seems like a loss to me, because I
can no longer run a generic, identical sendmail.cf on multiple machines.
It would be okay if sendmail allowed me to match a multiple token macro
(that is, 'user@$w' should match 'user@ocean.harvard.edu'), but it doesn't.
Am I missing something, is there a way around this without hardwiring
hostnames?  Fortunately, SUN 3.2 seems to do work in the presence of
domain servers (that is, sets '$w' to the hostname without the domain),
but I am stuck with either patching sendmail once on all my 4.3BSD machines,
or patching multiple sendmail.cf's whenever I make a change to the generic
version.  Yuk.

	Glen Dudek
	postmaster@harvard.harvard.edu