To send mail through the Wabash servers from either side of the firewall, the 
mail client software must be changed to use the "submission port" rather than the 
standard SMTP port.
Eudora:
Go to Tools|Options|Sending Mail.  Check "Allow Authentication" and 
"Use Submission Port."
Thunderbird:
Go to Tools|Account Settings|Outgoing Server.  Edit 
"smtp.wabash.edu": Change "Port" to 587, check "Use name and password", and enter 
username.
Mac Mail:
Go to Mail|Preferences|Accounts.  Click "Server Settings" under 
"Outgoing Mail Server."  Change "Server port" to 587, change "Authentication" to 
"password."  Enter username and password.
 
The POP/IMAP connections to the incoming mail server already work on both sides of 
the firewall, and do not need to be changed.