Outbound (only) email using sendmail

[Don Bentz]

I would like to confirm whether it is possible to send mail OUTBOUND only (i.e., Port 25 IN on the firewall turned off) to Internet (i.e., name@domain.com) addresses. I see from my sendmail.cf file it uses SMTP, which, according to RFC821 appears to require 2-way communication between 2 SMTP machines. I think this means, "NO, you can't"; Can somebody confirm this for me. I am quite confused about this. I am using a Smart relay host currently but am being pressured to discontinue using it and I really don't want to have to manage all the issues surrounding opening my server up to the Internet for inbound email to solve it. I am considering setting up another Windows 2000 to be my relay host, but continue to allow the other relay host to be my "masquerade" and receive the replies there.

[Geoff Wild]

You don't have to have sendmail running as a daemon in order to send outgoing mail - just disable it.

/sbin/init.d/sendmail stop

set SENDMAIL_SERVER=0 in /etc/rc.config.d/mailservs

add to cron:

# Make sure any queued mail is delivered, as sendmail isn't a daemon anymore
39 * * * * /usr/lib/sendmail -q

As far as port - good question as to whether you need it open both ways or not...

Rgds...Geoff