[Zope] Help with mail error -- Error Value: (111, 'Connection refused')

After switching machines around due to a crash/recovery. I find that I'm getting an error when I try to use methods which utilize the Mailhost object. I get "Error Value: (111, 'Connection refused')" I don't understand what could have caused this change, except for changing IP addresses. Any thoughts? I'm running on RH 7.3, Zope 2.5.1, Python 2.1.3. Does Mailhost need to use sendmail? Many thanks, Dan