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.

Related Posts

Retrying mail to AOL

I’m working on stuff for MAAWG so I’m really not all that up on what’s happening in the world of email recently. A lot of folks are commenting on my AOL post, and I’m hearing that queues are backing up and emptying as AOL makes changes.
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.

Read More

AOL: Still broken

I’m still hearing reports that AOL is still having problems accepting mail. I’ve also heard they’re still working on it. There is no information on when a fix may be finished.

Read More

AOL … again

A number of senders are reporting that they’re getting unusual responses from AOL servers. The responses include:

Read More