Path: utzoo!news-server.csri.toronto.edu!bonnie.concordia.ca!ccu.umanitoba.ca!herald.usask.ca!alberta!aunro!aupair.cs.athabascau.ca!atha!decwrl!elroy.jpl.nasa.gov!swrinde!zaphod.mps.ohio-state.edu!wuarchive!rex!uflorida!daytona.phys.ufl.edu!swiler
From: swiler@daytona.phys.ufl.edu (Tom Swiler)
Newsgroups: comp.sys.apollo
Subject: Re: sendmail.5.6.1+IDA .cf files
Summary: sendmail
Keywords: sendmail configuration
Message-ID: <27440@uflorida.cis.ufl.EDU>
Date: 14 Mar 91 00:30:04 GMT
Expires: 15 Mar 91 05:00:00 GMT
References: <7696@uceng.UC.EDU>
Sender: news@uflorida.cis.ufl.EDU
Organization: University of Florida Physics, CMT Group
Lines: 3

I had a similar problem, if memory serves me correctly.
If you are using the sys5.3 version of sendmail, try
using the bsd4.3 version instead.