Goto Edit | Preferences | Identity
In "Email Address", enter [username]@[yourdomain].com
In "Reply to...", enter whatever@[yourdomain].com
In "Mail server user name", enter [username]
Outgoing Mail(SMTP)* server: [yourdomain].com
Incoming Mail(POP3 or IMAP)server: [yourdomain].com
*Using SMTP Server
Per dialup session, you would need to be authenticated to use the SMTP(Outgoing Mail) server. This is to prevent spammers from gaining access to your SMTP server. Here is how you can be authenticated:
1) Get connected to the Internet
2) Start your email software.
3) Make sure there is no outgoing mail in your outbox.
4) Log into the POP server to check your email
5) Now you are authenticated and you should be able to send and receive email w/o any problems. As long as you don't quit the program and stay connected to the net, you wouldn't need to be authenticated anymore.
If your SMTP access is denied after trying the steps above, you would need to contact your ISP. It is likely that they are not allowing relay to outside
SMTP server. More and more ISP's are implementing this feature to prevent spamming.
There is a very easy workaround this. All you have to do is to use your ISP's
SMTP server. This does not effect how your email address appears on your outgoing emails. When
recipients to your message hits the reply button, they will see your email address at your domain name.