While in the process of solving a secure certificate issue with one of our customers I ended up having to debug an email issue for the same customer before continuing with the resolution of the primary issue (just have to love those “one-step forward, two-steps backwards and a sidestep” issues).
Anyway, the email issue involves SPF and it's a situation that frankly, never crossed my mind.
conman.org has an SPF record that basically states: “only hosts
listed as MX hosts for
conman.org and IP
addresses XXX.XXX.XXX.XXX through XXX.XXX.XXX.XXX are allowed to send mail
conman.org and no others.” No problem there, until
email is forwareded!
I sent a test message from
root@XXXXXXXXXXXX, which is then
forwarded to an account (that all
root@<the various servers at The
Company> get forwarded to) that ultimately ends up in my work mailbox.
Now, all email for The Company goes through a spam firewall, which, among
other things, checks for SPF. So, the mail message I sent went
rootmail@[The Company root catch-all account], but
when it hit the spam firewall at
Company root catch-all account] the mail was still
email@example.com, but it was coming from
the customer's server, which isn't listed in my SPF record (see above), so it was blocked from
Draconian SPF records break in the face of email forwarding. Email forwarding is a standard feature of email. SPF is pretty pointless without draconian records (well, non-draconian records means one can mark an email as suspicious but without support for such tagging why even bother?).
So why bother using SPF then?
I'm still having fun with the camera phone and its ability to take panoramic pictures (wow! What a neat feature!). Anyway, the shot above is of the walkway just outside The Corporate Offices of The Company, where you can bask in the expanse that is … The Company.
This shot is of The Office I share with P. That's P on the left (he's been feeling a bit pixelated all week) in front of his computer, and that's my computer on the right. The text you see is the screen saver, displaying some code I've written.
For both my friends from college (especially those that were at the New Year's Eve 1992/New Year's Day 1993 party) and for the Sunday Gamers crashing Gregory's office every few months between 2000 and 2002 (or there abouts) is a long night in the office (via Amanda Robbins).