request-answer should not reply to mailer-daemon et al

["Todd C. Miller" <Todd . Miller @ cs . colorado . edu>]

Relative to a patched majordomo-1.94.4.  Appologies if a
similar patch has been posted before.  I didn't see one on
ftp://sol.ccsf.cc.ca.us/majordomo-patches/1.94.4/

 - todd

--- request-answer-	Thu Apr 30 19:10:35 1998
+++ request-answer	Tue May  5 08:46:04 1998
@@ -30,12 +30,20 @@
 require "shlock.pl";
 require "majordomo.pl";
 
+$majordomo_dont_reply = $majordomo_dont_reply
+    || '(mailer-daemon|uucp|listserv|majordomo)\@';
+
 &ParseMailHeader(STDIN, *hdrs);
 $reply_to = &RetMailAddr(*hdrs);
 $reply_to = join(", ", &ParseAddrs($reply_to));
 
 die("request-answer: $reply_to is not a valid return address.\n") 
     if (! &valid_addr($reply_to));
+
+# robots should not reply to other robots...
+if ($reply_to =~ m/$majordomo_dont_reply/i) {
+    &abort( "$whoami: not replying to $1 to avoid mail loop.\n");
+}
 
 $in_reply_to = $hdrs{"message-id"} . ", from " . $hdrs{"from"};
 $list = $ARGV[0];