Mac OS X Mail.app Authenticated SMTP Configuration

To start, go to the Mail menu, and select "Preferences." Click the "Accounts" icon, and you should see the image below:
main

Click on "Add Account", and you should see the window below. If you are editing an existing account, be sure to click "Edit" instead of "Add Account." Click on "Outgoing Mail Server", and choose the "Add Server..." option. This will add a new SMTP server to Mail.app.
prefs

Now you should see the "SMTP Server Options" window, like the one below.
master password

The outgoing mail server should be set to "smtp.cs.umd.edu". Leave the server port as the default 25, and select the "User Secure Sockets Layer (SSL)" option.

We only support Password authentication currently.

Password with SSL: First contact staff and obtain a CS Kerberos5 password. Now, choose "Password" as the authentication method. Please make sure that you have checked SSL, as outlined above. Otherwise this will not work.
Enter your user name for "User Name", and your CS Kerberos5 password for the password.

Next, make sure that you have the newly created SMTP server selected:

Once it is selected, all further email from that account should be sent through that "smtp.cs.umd.edu".