If you use Outlook 2003 or outlook express the same settings below apply but the steps to get there differ.
Verify you have a working internet connection, ensure you can browse the internet.
Open Microsoft Outlook
Click Tools and choose Account Settings...
Click new to create a new email account.
Put a check mark in “Manually configure server settings or additional server types” and click next.
Leave the setting on Internet E-Mail and click next.
Fill in the fields below replacing “yourdomain.com” with your actual domain name. Then click the “More settings…” button.
Choose the 2nd tab “Outgoing Server” and put a check mark in
“My outgoing server (SMTP) requires authentication”, then click the Advanced Tab.
Change the “Outgoing server (SMTP): from 25 to 27 and click OK.
Click next and Finish to complete the setup.