Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!evax!texas!ylee
From: ylee@csl.dl.nec.com (Ying-Da Lee)
Newsgroups: comp.mail.sendmail
Subject: Re: Sendmail host canonicalization broken?
Message-ID: <1991Apr15.200923.11004@csl.dl.nec.com>
Date: 15 Apr 91 20:09:23 GMT
References: <1991Apr12.235346.28444@mp.cs.niu.edu> <12665@pt.cs.cmu.edu> <1991Apr14.002726.9334@mp.cs.niu.edu>
Organization: NEC America, C & C Software Development Lab
Lines: 49

In article <12665@pt.cs.cmu.edu> ddean@rain.andrew.cmu.edu (Drew Dean) writes:
>In article <1991Apr12.235346.28444@mp.cs.niu.edu> rickert@mp.cs.niu.edu (Neil Rickert) writes:
>| 2.  Here is a good reason for turning off RES_DNSRCH:
>|	Suppose someone in your French department has a machine called
>|	eiffel.fr.mcc.com.  (OK.  You aren't a University, and you don't
>|	have a French Department.  But let's pretend here for a moment.)
>|	Now imagine you wish to send a message to 'user@eiffel.fr' -- the
>|	real eiffel.fr, that is, in France.  You can't if RES_DNSRCH is
>|	turned on, because it will always go to your French department.
>
>I'm not a real sendmail hacker (I got 5.61 working on my machine and quit
>at that), but if you can't send mail in this case to user@eiffel.fr. <--
>note the final period !, then sendmail is _really_ broken.  The final period
>is defined to indicate this is a complete domain name, and should not be
>expanded...

In article <1991Apr14.002726.9334@mp.cs.niu.edu> rickert@mp.cs.niu.edu (Neil Rickert) writes:
>
> RFC1123 specifically warns that addresses with a final period are INVALID.

I think Drew made a very valid point.  People who know enough to put an
ending priod should have their words respected.

Furthermore, RFC 1123 (I assume it's the last item of section 5.2.18
that Neil is refering to) does not automatically comes into play here.
It states
	Some systems over-qulaify domain names by adding a trailing
	dot to some or all domain names in addresses or message-ids.
	This violates RFC-822 syntax.

It would be a clear violation of RFC-822's syntax if a mailer
used user@eiffel.fr. as the recipient address on the envelop.
Still, there is no reason why the mailer couldn't resolve
an input of 'user@eiffel.fr.' into host 'eiffel.fr.' (with
ending period) and recipient 'user@eiffel.fr' (without ending
period).  Only the sending system and DNS, which routinely
accepts ending period in a domain name, see the host part.
Nowhere else is it used in the e-mail.

This way, people in mcc.com can send mail to France with
user@eiffel.fr. (with period) and to its own French department with
user@eiffel.fr (without period).


	Ying-Da Lee			(214)518-3490
	C&C Software Development Lab
	NEC America			(214)518-3990 (FAX)
	ylee@csl.dl.nec.com
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