Re: Sendmail configuration

[Jonathan Byrne <jq@example.com>]

A.Sajjad Zaidi (sajjad@example.com) wrote:

> Im trying to setup sendmail to act as an smtp server, but I dont want
> just anyone to be able to use it for relaying. Is there an option to
> authenticate the user based on the system password?

Any recent sendmail should be configured by default to not relay for
any non-local domain.   Overriding that behavior carries a high price,
since spammers will find it and use it, and you quickly find the
machine listed with RSS and ORBS.

Sendmail (and other MTAs) can also be configured to do authenticated
SMTP, in which a password is required (note, however, that this is
for use on your outbound SMTP servers, not your MXes).  If you don't
have the O'Reilly Sendmail book, you need to get it before messing
to much with your configuration.  This should (can't say for sure;
we no longer use sendmail and I don't have a current copy at hand)
also describe authenticated SMTP, if you need to use it.  If you 
must, for any reason, configure your outbound SMTP as an open relay,
you *must* use authenticated SMTP.  Most (not all) win/mac mail
clients now support auth smtp, I believe.

Jonathan