What do I put for both incoming and outgoing mail server?
Your outgoing and incoming mail server would be:
mail.yourdomain.com (make sure you replace yourdomain.com with your actual domain name.)
If you have recently changed your domain's DNS then mail.yourdomain.com may not work until your DNS resolves to our servers, until then you can use the IP address or hostname of the server to connect temporarily. (This information is available in your welcome email)
Incoming mail port is 110
Outgoing port is 25, since most ISP's block port 25, you can use port 26 as an alternative.
The outgoing and incoming mail server settings will be the same for your addon and parked domains.