brian@ucsd.EDU (Brian Kantor) (02/05/88)
The "I refuse to talk to myself" error in sendmail is usually caused by
a conflict between the hostname in the address and the rules and/or
"my hostname" class ("Cw") in sendmail's control file. What has
happened is that your sendmail has processed the incoming mail and
decided that it is NOT destined for delivery upon the local host, but
should be delivered via one of the SMTP mailers (i.e. Ethernet), but
the hostname given winds up resolving to itself so when it opens the
SMTP connection, it winds up trying to talk to itself.
Perhaps the most common cause for this is that you have multiple names
for the host in your /etc/hosts file (or nameserver database) and
someone is mailing to one of these that ISN'T your system's HOSTNAME
(as returned by the 'hostname' function).
There are a couple of solutions:
A) you could add the other hostnames for your system to the Cw
class (which often does not appear explicitly in the sendmail.cf
- it is set by default to your 'hostname'), or
B) [perhaps better] you can use the $[$] operator to convert the
hostname in the address to its canonical (primary) name in
ruleset 0 before mailer resolution, and optionally in the various header
processing rulesets to ensure that only canonical names leave your
mailer.
C) you could delete the nicknames for your host.
One difficulty comes with hostnames that are set to a dotted-domain
name: most sendmails have "." as a parsing character, so it isn't
possible for you to match $=w with, say, "cyberpunk.ucsd.edu". You
can solve this in several ways; I chose to define a DDucsd and DTedu
and do the comparison in parts.
No, you really don't want a copy of our sendmail.cf file. I'll
send it to you if you ask, but it's big, confusing, and HEAVILY
hacked so I'd recommend you start with a more standard one first.
Arpanauts will find a copy in the anonymous FTP area on host 'UCSD.EDU'.
Hope this helps.
Brian Kantor UCSD Postmaster & Chief News Weenie
UCSD Office of Academic Computing
Academic Network Operations Group
UCSD B-028, La Jolla, CA 92093 USA
brian@ucsd.edu BRIAN@UCSD ucsd!brian