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From: rickert@mp.cs.niu.edu (Neil Rickert)
Newsgroups: comp.mail.sendmail
Subject: Re: sendmail resolver options
Message-ID: <1990Sep27.231037.15459@mp.cs.niu.edu>
Date: 27 Sep 90 23:10:37 GMT
References: <1990Sep27.201736.4938@turnkey.tcc.com>
Organization: Northern Illinois University
Lines: 38

In article <1990Sep27.201736.4938@turnkey.tcc.com> jackv@turnkey.TCC.COM (Jack F. Vogel) writes:
>
>I have a question that I hope someone out there might enlighten me on.
>In the 5.61 as well as 5.64 code deliver.c just before it calls the
>routine getmxrr() it is setting the resolver options as follows:
>
>	_res.options &= ~(RES_DEFNAMES | RES_DNSRCH) 	/* XXX */
>
>Notice the illuminating comment :-}. My question is why one would
>want to do this, it means that the default domain name is not appended
>to a fully unqualified hostname, nor is a search performed. I would
>think one WOULD want these options on, is there something I am missing
>here??

  Firstly most versions of 'sendmail.cf' have already processed the
host name with the $[ ... $] which should have fully qualified it already.

 ----
  Secondly, assume my default domain is  CS.NIU.EDU

  Assume, moreover, that there is an MX record in the domain server
data base:

*	IN	MX	0	some.host.somewhere.

  Now suppose I am mailing to 'jackv@turnkey.tcc.com'.  If that statement is
not present in deliver.c, the resolver tries qualifying in the domain:-
	turnkey.tcc.com.cs.niu.edu

 Bingo.  It matches the MX wildcard record.  The mail is successfully delivered
to the wrong place.

  Not a real good idea.
-- 
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  Neil W. Rickert, Computer Science               <rickert@cs.niu.edu>
  Northern Illinois Univ.
  DeKalb, IL 60115.                                  +1-815-753-6940