These instructions assume you've already set up an e-mail account in the Mac OS X "Mail" program and you want to verify the outgoing mail "port number".
Using the correct port number makes sure your outgoing mail won't be blocked in the future. It's especially important for laptop computers that use different wireless networks when traveling. Many hotels and ISPs will block outgoing mail if you don't follow these instructions.
If the Mail program isn't already running, start it now.
Using the menu bar at the top of the screen, click Mail, then Preferences:
The preferences window will appear.
Navigate to the "Account Information" screen shown below:
To do this:
Click the "Outgoing Mail Server (SMTP)" menu and choose Edit Server List...:
The outgoing mail settings window will appear.
Click Advanced to view the port number. If necessary, change the "server port" to 587, so it looks like this:
In some cases, the server port will already be set to 587. If so, you don't need to change anything.
Click OK to close the outgoing mail server settings window, then click the red close button in the upper-left corner of the Accounts window.
You've finished setting up Mail! You should now be able to send mail from any network, even if that network blocks most connections to other mail servers.