The following steps will assist you in changing your outgoing mail settings in Entourage 2008:
1. Open Entourage.
2. Click on Tools, followed by Accounts.
3. Click on Mail and then select your e-mail account.
4. Click on the Edit button
5. Under Sending Mail, enter the name of the outgoing server: If your domain name is example.com then enter: mail.example.com
6. Click on Click here for advanced sending options.
7. Check Override default SMTP port.
8. If necessary, change the port to: 587
9. Check SMTP server requires authentication and ensure that Use same settings as receiving mail server is selected.
10. Click on the box in the upper-left corner to close the pop-up window.
Click on the 'Ok' button to save your settings.