AOL Updates Spam Filtering

Over on the AOL Postmaster blog, Lili Crowley announced yesterday that AOL has made changes to their spam filtering system. Specifically, more senders may be subject to blocking with CON:B1 errors. AOL’s website explains that CON:B1 errors indicate that an IP address is being  blocked “due to a spike in unfavorable e-mail statistics.” This strongly suggests that a sender blocked with a CON:B1 error message has a negative sending reputation. This is yet another data point as to how ISPs have been tightening up spam filtering and reputation requirements over the past few years. What you might have been able to deliver five years ago, you might not be able to get delivered today.

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Retrying mail to AOL

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One thing people have been asking me is if they should retry mail to the addresses that are bouncing. I say yes, absolutely. Some of the error messages are related to real filters, but there seems to be quite a bit of slop in the filters these days. I think, though, that the recipients do exist and removing the addresses from future mailings is premature.

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It's Thursday: AOL must be having problems

And, in fact, they are.
This time I’m seeing random reports of FBL failures. Some folks are seeing a significant (more than 50%) decrease in FBL emails. Other folks are reporting FBL reports that aren’t really FBL reports, but instead look like failed code output.
If you’re seeing this kind of problems it’s not just you.
As always, people at AOL are working to fix things and cooperating with people in the sending community who are having this problem. In other news, I found out last week that the one Really Smart Mail Guys I thought was still there is still at AOL but is no longer in their mail division. That means that the guys who built the AOL version of Skynet have left it to its own devices. Be afraid. Be Very Afraid.
 
 

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AOL bounces and false positives

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The other one is a bit more interesting. The error message a lot of people are seeing is 554/421 RLY:SN. Senders should only be getting this error message when they are sending email from a banned address.

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