Finally got my dedicated RaQ 4. Anyway, while I'm quite pleased with it in general, there is one little problem: email addresses are always like username@www.domain.com, instead of just username@domain.com. While I have a good idea of how to solve this problem, I'd be much obliged if you could tell me the simplest way of fixing this.

Thank you in advance. :)

In Web server aliases put
yourdomain.com

In e-mail aliases put:
yourdomain.com, www.yourdomain.com

Works for me.

I put mydomain.com in web server aliases. However, I put mail.mydomain.com in the email aliases form. Now I know where I went wrong. :)