Sendmail Anti-Spam Control

[xyle_one]

I have a (near) default configuration of Sendmail version 8.13.1.

I do not know too much about sendmail, or email servers for that matter. But I did have some questions. I understand that I am at risk for being an open relay. But I also read that by default Sendmail disables this, and only allows the hosts in the local domains to relay mail. I am currently reading the documentation on this, but it's not exactly clear. What exactly do I need to do to ensure that I am not open?

[Void Main]

I don't know what the default sendmail configuration is if you get sendmail in a tarball from sendmail.org, only what the default is as packaged by Red Hat. The Red Hat package is configured by default to only listen on the loopback adapter so there is no chance of anyone even connecting to your smtp port. However, assuming you have port 25 exposed to the outside world it would depend on your settings primarily in your /etc/mail/sendmail.mc (assuming you generate your sendmail.cf based on the settings in sendmail.mc) and your /etc/mail/access files. If you are unsure there are free services out there that will test to see if you're configured as an open relay or not:

http://www.ordb.org/submit/

http://www.google.com/search?hl=en&lr=& ... tnG=Search

[xyle_one]

Great, thank you. I am using Redhat by the way.