Forum Moderators: phranque
1. Figure out what ip your mail server uses. You can do this by sending an email to one of your outside addresses and looking at the headers.
2. You should probably make sure your reverse dns is correct while you're at it, ie the reverse dns on your mail ip should be mail.example.com (or similar). If you are on a shared email server this might not be possible.
3. If you use a web-based dns control panel (like if your registrar hosts your dns), it will probably have a spf wizard built in. Try it. Otherwise, go to [openspf.org...] and put your domain in the wizard. It will generate your spf record for you, then give that record to your dns server.
Did I miss anything?