Full e-mail message headers provide invaluable information when trying to track down a problem. This guide will show you how to view full headers in several popular e-mail clients and online e-mail services.
If you contact support regarding an e-mail problem one of the questions we will ask you is how you are accessing your e-mail. If you are using a client such as Outlook, Outlook Express, Thunderbird, Mac OS X Mail, or any other modern e-mail application we will ask if you are using POP3 or IMAP for your incoming e-mail.
There are pros and cons to both methods, but with some careful consideration of what is most important to the user(s) you can make a (well) informed decision.
Many large ISPs restrict the access to port 25 on their networks to attempt to stem the tide of spam sent out from compromised computers. If your ISP is restricting access to port 25 you will not be able to send e-mail through your server, but by enabling SMTP (Simple Mail Transfer Protocol) on a different port, like 26, it may be possible to circumvent the restriction.
This tutorial will walk you through the steps required to set up a new email account in Mail (aka Mail.app aka MacMail), the built-in email application that comes with Mac OS X.