SPF records: not really all that important

I’ve been working through some Hotmail issues with a client over the last few months. One of the things that has become clear to me is how little Hotmail actually does with SPF records. In fact, Hotmail completely ignored my client’s SPF record and continued to deliver email into the inbox.
This isn’t just a sender that had a “well, we think most of our email will come from these IPs but aren’t telling you to throw away email that doesn’t” record. In fact, this client specifically said “if email doesn’t come from this /28 range of email addresses, then it is unauthorized and should be thrown away.” The email was being sent from an IP outside of the range listed in the SPF record.
As part of the process involved in fixing the delivery problems, I had the client update their SPF record and then I enrolled their domain in the SenderID program at Hotmail. This didn’t have any effect, though. Hotmail is still not checking SPF for this client. When I asked Hotmail what was going on they said, “We do not do lookups on every sender’s mail.”
So, there you have it folks. The last bastion of SPF/SenderID has abandoned the technology. Even a totally invalid SPF record doesn’t matter, mail can still reach the inbox at Hotmail.

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If there were no spam filters keeping all the crap people get out of their inbox (in my case over 1000 messages a day) then spam would overwhelm even the most dedicated email junkie. I couldn’t do my job without my spam filters, and in fact the recent rash of virus spew is ending up in my inbox and making finding real mail a problem. I do a lot of sorting before mail ever hits my inbox, and I’m still struggling to deal with the couple hundred “your order has shipped!” and “please her tonight!” emails that my local bayesian filters haven’t caught up to, yet.
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