> I'm going to develop a web-based email system. The user
>information will be in MySQL database. The question: how to make sendmail
>to check if user exists in MySQL table? Have already somebody solved this
>problem? Is there a patch for sendmail to authentificate against external
>SQL database? May be other MTA, but sendmail if preferable.
It would probably be easier to roll your own server that supported SMTP (no
kidding!) or get one of the sendmail clones than hacking sendmail - the
code's a mess.
If you use 'sendmail -bt' on the back end, you can parse the output and
figure out if the message is deliverable. Is that what you're trying to do?