Check Sender Information?

[TRACKS]

Can anyone enlighten me on how I can Check Sender Information and reject mail from unresolvable domains?

[dougp23]

install spamassassin. it does all that.

[grahamk]

from /etc/mail/sendmail.mc

dnl # We strongly recommend not accepting unresolvable domains if you want to
dnl # protect yourself from spam. However, the laptop and users on computers
dnl # that do not have 24x7 DNS do need this.
dnl #
dnl # FEATURE(`accept_unresolvable_domains')dnl


The only thing to consider is that with a default install of Scalix, sendmail does not accept the incoming mail, but gets handed the mail from scalix. I am using mailwasher, and as part of getting DNSBL working, I have configured sendmail to accept all incoming mail.