Need setup help for Pather server POP authentication via Kerberos

[awingnut]

I have my mail server set up for kerberos authentication. However, when I try to set up my mail client the server does not seem to be listening to the ports I think it should. I believe Kerberos should use port 587 but I get an 'unable to connect to port 587' error. What port should the mail client be using for Kerberos authentication?

Also, since I'm sure this will come up if I can get the thing to work, if the user is already authenticated to the server via LDAP will the mail server require the password again?

TIA.