Sendmail: rejecting connections?

Hi everyone,

I'm fairly new to Linux, (running 6.0) but so far, I do like it.... I hope
to learn something new from you folks! My first question regards an error
I'm getting on my server, "rejecting connections on port 25: Min free: 100"

Any thoughts? At first I thought I was getting spammed, bombed, or
something..... my incoming mail is currently not working.... don't know
about outgoing...

thanks for any help you can give, and I hope to see a few of you at the next
meeting!

-Rick