What is port 110?

[Mark Swanson]

I just installed a new 200 gig drive in my PowerMac G4, along with the 
original 80 gig drive.  Installed OS 10.2.3 on both, clean install on 
the new drive and installed over 10.1.5 on the original drive.  Both 
seem to work fine.  The original "main" drive has mail and browser 
working fine.  The same set up on the new drive keeps telling me the 
the mail program and browser can't communicate on "port 110".  I 
checked all system prefs for port information, no go.  How do I change 
(if that is what I need to do) the port the new drive/system is using?  
When I changed the drive in my TiBook and upgraded to 10.2.3, no 
problems with mail or browser.  Is this a terminal operation?  mark