Newsgroups: comp.mail.sendmail
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!magnus.acs.ohio-state.edu!csn!stan!kucharsk
From: kucharsk@Solbourne.COM (William Kucharski)
Subject: Re: need help with MX records
Message-ID: <1991Mar20.183811.2025@Solbourne.COM>
Organization: Solbourne Computer, Inc., Longmont, CO
References: <1991Mar20.002804.2705@borland.com> <1991Mar20.035906.30388@mp.cs.niu.edu>
Date: Wed, 20 Mar 1991 18:38:11 GMT

In article <1991Mar20.035906.30388@mp.cs.niu.edu> rickert@mp.cs.niu.edu (Neil Rickert) writes:
 >In article <1991Mar20.002804.2705@borland.com> sidney@borland.com (Sidney Markowitz) writes:
 >>We're running Sun OS 4.1.1 on a Sun 4 (Sparc), using the domain name
 >>server and sendmail.mx software supplied by Sun. Our site has an IP
 >>address on the Internet. For some reason mail addressed to hosts that
 >>are not on the Internet, but are reached via MX records, bounces with a
 >>an error about the host name not being found. I added the resolver
 >
 > I have used sendmail.mx on a Sparc with no difficulty.  But you have to use
 >sendmail.mx.  You cannot use sendmail.nomx even if the resolver code is in
 >the shared library.
 >
 > I have seen your problem before.  It is usually caused by not understanding
 >what it means to run sendmail.mx...

One other thing which I've seen happen may or may not be fixed in 4.1.1 but was
broken in 4.1.  Under 4.1, if you have a local wildcard MX record, mail to any
host which has an MX record but is not directly connected to the internet will
bounce.  Here's what 4.1's sendmail.mx does:

If there's a wildcard MX for your domain (say "foo.com"), sendmail.mx will
attempt to lookup hosts as name.domain, e.g. it will attempt to lookup the
host "bar.com" as "bar.com.foo.com."  It will attempt to lookup both MX and A
records for that host.  Since it finds a MX record due to the wildcarding, it
will attempt to lookup an A record, but won't find one (naturally).

It will then attempt to lookup an A record for "bar.com," and if it doesn't find
one it will declare the host unknown.  It WILL NOT attempt to lookup a MX
record for "bar.com"!

The 4.0.3 sendmail.mx and sendmail5.65 handle this situation correctly.

-- 
| William Kucharski, Solbourne Computer, Inc.     | Opinions expressed above
| Internet:   kucharsk@Solbourne.COM	          | are MINE alone, not those
| uucp:	...!{boulder,sun,uunet}!stan!kucharsk     | of Solbourne...
| Snail Mail: 1900 Pike Road, Longmont, CO  80501 | "It's Night 9 With D2 Dave!"
