Filtering adjustments at Hotmail

I’ve been seeing a lot of discussion on various fora recently about increased delivery issues at Hotmail. Some senders are seeing more deferrals, some senders are seeing more mail in the bulk folder. Some senders aren’t seeing any changes.
This leads me to believe that Hotmail made some adjustments to their filtering recently. Given some senders are unaffected, this appears to be a threshold change or a calculation change, tightening up their standards. The changes have been around for long enough now it does look like the filtering is working as intended and Hotmail is not going to roll these changes back.
So what can you do to fix delivery of mail that was good enough at Hotmail a few weeks ago and now isn’t?

  1. Look at your data hygiene. Do you have older addresses that haven’t responded in any way recently? Try removing that data from your mailings for a week or two and see if that improves your delivery.
  2. Check your content for URLs that might be advertised or spammed in mail from IPs other than your own. Use domains you have complete control over in all your mail, both for links and anywhere in the text.
  3. Contact recipients through a non email channel and ask them to add your address to their address book.
  4. Look at performance of your lists per acquisition channel, maybe one of your acquisition processes is giving you poor data. Removing these addresses may improve your overall reputation and get your mail into the inbox.

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Link roundup June 18, 2010

Hotmail has released a new version of their software with some changes. Return Path discusses the changes in depth, but there are a couple that senders may find helpful.

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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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Reputation monitoring sites

There are a number of sites online that provide public information about reputation of an IP address or domain name.

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