sendmail trouble

[John D. McCalpin]

The mailer on my machine has recently started returning a significant fraction
of the messages bound for me from other internet nodes.  Fortunately, on one
occassion, my machine did not know the IP address of the sending machine, so
it could not return it, and I manually snatched it out of /usr/spool/mqueue.

Specifics:
	Silicon Graphics IRIS 3030 running SGI's UNIX revision 3.5
		(SYS V.2 plus BSD 4.[23] extensions, including BSD mailer)

The df?????? file that my machine was trying to return contained:
====================================================================
   ----- Transcript of session follows -----
>>> HELO masig1.ocean.fsu.edu
<<< 553 masig1.ocean.fsu.edu I refuse to talk to myself
554 <mccalpin at masig1.ocean.fsu.EDU>... Service unavailable: No such file or directory

   ----- Unsent message follows -----
Received:  by masig1.ocean.fsu.edu (5.15/25-eef)
	id AA08246; Fri, 22 Apr 88 16:31:28 EST
Date:     Fri, 22 Apr 88 15:26:50 EST
From: "David F. Rogers" <dfr at USNA.MIL>
To: mccalpin at masig1.ocean.fsu.EDU
Subject:  subject
Message-Id:  <8804221526.aa02036 at CAD.USNA.MIL>

message......
====================================================================
The qf??????? file is uninteresting because it appears to pertain
only to my machine trying to return the above message to usna.mil :
====================================================================
P577750297
T577747897
DdfAA08248
MDeferred: Not a typewriter
SMAILER-DAEMON
R<dfr at USNA.MIL>
H?P?return-path: <MAILER-DAEMON>
Hreceived:  by masig1.ocean.fsu.edu (5.15/25-eef)
	id AA08248; Fri, 22 Apr 88 16:31:28 EST
H?x?full-name: Mail Delivery Subsystem
Hsubject: Returned mail: Service unavailable
Hdate:     Fri, 22 Apr 88 15:26:50 EST
HFrom: "David F. Rogers" <dfr at USNA.MIL>
HTo: <dfr at USNA.MIL>
HTo: mccalpin at masig1.ocean.fsu.EDU
Hsubject:  subject
Hmessage-id:  <8804221526.aa02036 at CAD.USNA.MIL>
==================================================================
I will not bog down the net with my sendmail.cf program.  It otherwise
works, and was pulled off of an ULTRIX 2.0 site which occassionally
has the same trouble with mail bouncing.....

Has anyone seen this particular peculiarity before?
I would greatly appreciate any pointers.....

Please reply to:		mccalpin at nu.cs.fsu.edu