Your Incoming Mail Server (POP3) and Outgoing Mail Server (SMTP) server address is mail.yourdomain for example: mail.example.co.za
Please note. For SMTP to work successfully, you need to allow POP-before-SMTP. In most email applications, this is refered to as "My outgoing mail server requirers authentication". You then need to supply your POP3 username & password for it to work. Microsoft OUtgoing does offer a feature called "Use the same settings as my incoming mail server" This would be the prefered option to use.