How to change your SMTP port on Mac OS X Mail.app Print

To change the outgoing mail port to 26 on Mac Mail.app:

1. Open Mail.
2. Click the Mail menu >> then click Preferences.
3. Click the Accounts icon.
4. Click the Account Information tab.
5. Expand the Outgoing Mail Server (SMTP)
6. Choose Edit SMTP Server List
7. Change to Advanced
8. In the Use Custom Port box, type the port number (26).
9. Click the OK button.
10. Restart Mail.