I am flabbergasted to say the least. I came back to work today after the Christmas break, and every one of my clients that have an SPF record are having problems sending e-mail to domains that use Postini (they use Sender ID filtering), and any domain that has Sender ID filtering enabled.
I thought maybe a user might have messed with the server until i was told ALL my clients are having the same problem. I went through each one of them, one by one, and verified all SPF records were correct, and passed validation (i use http://www.kitterman.com/spf/validate.html
). I made sure everyone had the same IP and didn't start using smart-hosts. I checked each domain from here ( http://old.openspf.org/why.html
) and ALL passed.
Every domain having the problem has had their SPF record in place for over a year, with no issues. I have checked MXToolbox to see if anyone was on a blacklist, and all were clean.
Was there an update that i'm un-aware of? I need this resolved ASAP, and i have no idea what the problem could be.
Note: Every domain i manage is a Windows network using Exchange, not that it matters.