Sender Policy Framework

• Google's approach to email
• Google Apps for Administrators - SPF

The SPF record for Gmail is a redirect to _spf.google.com with an SPF NEUTRAL ?all result for mails from other IPs. Gmail offers no SPF FAIL protection at the moment.

Google Apps (for domain owners using Google as hoster) proposes to use v=spf1 include:aspmx.googlemail.com ~all with an SPF SOFTFAIL ~all result for testing. At the moment the "included" aspmx record is another redirection to _spf.google.com. Better don't try to eliminate the redirection, they might need to change it in the future.

See a thread on the SPF discuss list and a follow-up in the GMail group under Gmail's SPF implementation doesn't care about "fail"?.