Recently I found out that mail I sent from this domain ( was being flagged as spam by Gmail. That is odd, because I have (correctly, I believe) defined the SPF records for this domain and it should be recognised as legitimate. I researched a bit, and came to a conclusion that other users have come to as well:

Gmail flags as spam Google Apps emails coming from Google’s SMTP server. I set up a new account and sent emails from Thunderbird and from Google Apps’ web interface, and surely enough, the Thunderbird one got marked as spam. This is a very serious issue, because Gmail users (and perhaps others) don’t receive my mail.

Please comment if it has happened to you or if you think I am doing something wrong. Perhaps I need to add an SPF record for every IP I send mail from? That’s unreasonable and very impractical, since my connection has a dynamic IP.

If you have a Google Apps domain, I urge to you do this test to find out if your messages are marked as spam. Send mail to a Gmail user who doesn’t have you in their contact list (otherwise your message will pass) and see which gets marked as spam and which doesn’t. I would also appreciate it if you would leave comments detailing the results of this test.

UPDATE: Well, I confirmed that my SPF settings are correct (Gmail tells you in “View original message”), but the exact same message sometimes gets classified as spam and sometimes as ham. I don’t know what’s going on, if anyone has any idea please leave a comment.

UPDATE 2: The SPF line (TXT DNS record) I added to my domain to make this work is v=spf1 a mx ~all, which is a bit different than what Google says. It seems to work fine now.