[comp.mail.sendmail] How to fail mail

meggers@orion.oac.uci.edu (mark eggers) (02/09/90)

I have an interesting problem that has appeared recently in setting up a
domain mailer. I am using sendmail 5.61 plus the IDA 1.2.8 patches, plus
UIUC's ph/qi/phquery system. In the nameserver files, I have two A record for
mydomain.edu, which are the two hosts that will redeliver alias@mydomain.edu.

For the most part, the system operates smoothly. However, some people have
configured MMDF on other systems to be 'helpful' to the user. If a user
tries to send mail to foo@unknown.mydomain.edu, MMDF has been configured to try
adding several default domains to unknown.uci.edu in order to find a match 
(if a DNS query for unknown.mydomain.edu fails). When this fails, MMDF then
starts chopping off lefthand parts of unknown.mydomain.edu, and trying to
deliver to the resulting righthand side (ie., mydomain.edu). Since
mydomain.edu now exists, it gets delivered to one of the mail servers.

Now the fun starts. The external address has been changed so that the mail
is delivered to mydomain.edu. The address looks something like

@mydomain.edu:foo@unknown.mydomain.edu

However, the To: address still looks like

foo@unknown.mydomain.edu

Thus, the mechanism for resolving alias@mydomain.edu is not involked. Mail
hops around for 17 counts and dies.

I would like to be able to recognize this as a typo and fail the mail.

What I really think should happen is that MMDF shold not be configured to
do what it does, but the people running the MMDF systems have refused to
change the configuration - stating that their users are used to occaisional
bounced mail and the 'helpful' advantages of this configuration far outweigh
any disadvantages.

Blech - any thoughts on how to fix this would be greatly appreciated.

/mde/