Sender Policy Framework

I've set up records, how do I test/validate/check them?

There are two types of SPF testers available. There are those that you send e-mail to, which are good for testing how actually e-mail will respond from the computer you are sitting at. There are also those that let fill in the appropriate information and can simulate an SPF check from anyone and from anywhere.

The Tools page has information on specific test tools known to be available.

If you run your own DNS server, you can use the exists: mechanism to capture information on where mail from your domain is being sent from. This example, exists:CL.%{i}.FR.%{s}.HE.%{h}.null.spf.altavista.com, is the prototypical example of this published by altavista.com in 2003. The example will log the IP address, MAIL FROM address, and HELO name every time the record is checked. There are other macros available to capture other information in your DNS logs as desired.