What to do if you're blocked by Hotmail

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One of the things I often get asked by people who email me are requests for help.  The specific request is that the person is sending mail to Hotmail but the messages are not getting through to the recipients email inboxes.  Our divisions, Hotmail and Exchange Hosted Services, are separate but here are some of my tips on getting your email through if you're having a problem with Hotmail.

  1. Make sure you have Forward-Confirmed Reverse DNS set up.  This means that the IP you are trying to send from has a reverse DNS entry, and the domain you are sending from should resolve to an IP address.

  2. It's usually a good idea to have your SenderID or SPF records set up.  Microsoft has a SenderID wizard here that you can use to figure out what your SPF records will look like.  Keep in mind Hotmail's interpretation of SPF records are used in conjunction with their SenderID implementation, which means they use your SPF version 1 records an apply them to the PRA.  If you have no idea what I am talking about, I suggest you read my series on sender authentication, paying special attention to parts 14 through 18.

  3. If you have sender authentication start up, that helps with deliverability.  The next thing to do is figure out whether or not your system is part of a botnet or infected with a virus and is sending out spam without your knowledge.  To check this, try going to DNS stuff and seeing if your IP is on any of those blocklists.  If it is, that could explain why Hotmail is blocking your mail.

  4. Another place you can try is Senderbase.  Senderbase will allow you to drop in an IP and get traffic pattern statistics.  If you see that your IP has a huge increase in traffic, there's a good chance your system is infected and is spamming.

  5. When all is said and done, you can escalate to Microsoft themselves.  There are two places you can go, the first is https://postmaster.live.com/.  That's the MSN Postmaster and they have a bunch of tips on email deliverability problems to Hotmail (also known as Windows Live Mail... which is much more cool).

  6. This information is on the Postmaster site, but you can also go to Microsoft's Smart Network Data Services page, https://postmaster.live.com/snds/.  This page allows administrators to request access to more information that Hotmail uses to base their decisions.  You can get quite a bit of historical data.

So that's the process that I would use if you're blocked by Hotmail.