Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!usc!ucsd!brian
From: brian@ucsd.Edu (Brian Kantor)
Newsgroups: comp.mail.sendmail
Subject: Re: Problem with MXs in Sun sendmail
Message-ID: <18507@ucsd.Edu>
Date: 6 Sep 90 19:26:32 GMT
References: <1267@kluge.fiu.edu>
Distribution: na
Organization: The Avant-Garde of the Now, Ltd.
Lines: 55

In sendmails 5.59 thru 5.64, there is a bug in domain.c that doesn't
properly compare MX names with hostnames - it doesn't use the FQDN of
your local host, so if your local hostname isn't set to a FQDN but is
instead a simple hostname (as most Suns are), the MX (which is fully
qualified) will not match to the local hostname, and you'll try to open
a connection to yourself - getting the 'not recognized as local'
(formerly, 'I refuse to talk to myself') error.  I assume Sun's
sendmail has the bug too.

The following patch (to 5.64) fixes that; it also adds a bit more
debugging that I used to figure this out.
	- Brian


*** ../../sendmail.64.virgin/src/domain.c	Tue Jun  5 18:27:44 1990
--- domain.c	Thu Jun 21 12:00:27 1990
***************
*** 55,61 ****
--- 63,79 ----
  	querybuf answer;
  	int ancount, qdcount, buflen, seenlocal;
  	u_short pref, localpref, type, prefer[MAXMXHOSTS];
+ 	char localhostfqdn[MAXNAME];
  
+ 	if (tTd(8, 1))
+ 		printf("getmxrr: res_search(host=`%s',MX)\n", host);
+ 
+ 	localpref = 0;
+ 	strcpy(localhostfqdn, localhost);
+ 	getcanonname(localhostfqdn, MAXNAME);
+ 	if (tTd(8, 2))
+ 		printf("getmxrr: \tlocalhost=`%s'\n", localhostfqdn);
+ 
  	errno = 0;
  	n = res_search(host, C_IN, T_MX, (char *)&answer, sizeof(answer));
  	if (n < 0)
***************
*** 119,125 ****
  		if ((n = dn_expand((char *)&answer, eom, cp, bp, buflen)) < 0)
  			break;
  		cp += n;
! 		if (!strcasecmp(bp, localhost)) {
  			if (seenlocal == 0 || pref < localpref)
  				localpref = pref;
  			seenlocal = 1;
--- 137,145 ----
  		if ((n = dn_expand((char *)&answer, eom, cp, bp, buflen)) < 0)
  			break;
  		cp += n;
! 		if (tTd(8, 2))
! 			printf("getmxrr: MX '%s' = %d\n", bp, pref);
! 		if (!strcasecmp(bp, localhostfqdn)) {
  			if (seenlocal == 0 || pref < localpref)
  				localpref = pref;
  			seenlocal = 1;