Russell from Port25 posted a comment on my earlier post about changes at Comcast.
Our (Port25) understanding is that Comcast is rate limiting such that they’re only accepting 6 recipients per second per sending IP.
This matches what I’ve been hearing from other bits of the industry over the last few days. I am recommending clients close the connection between each set of 6 email addresses.
Earlier this week a question came up on a mailing list. The questioner recently started seeing an increase in rejections to @aol.com addresses. These rejections said
Read MoreSources tell me that AOL announced on yesterday’s ESPC call that they are now, and have been for about a week, checking DKIM inbound. This fits with a conversation I had with one of the AOL delivery team a month or so back where they were asking me about what senders would be most concerned about when / if AOL started using DKIM.
The other announcement is that AOL, like Yahoo, would like to know how you categorize your outgoing mail stream as part of the whitelisting process.
Both of these changes indicate to me that AOL will be improving the granularity of their filtering scheme. DKIM signing will let them separate out different domains and different reputations across a single sending IP address. The categorization will allow AOL to evaluate sender statistics within the context of the specific type of email. Transactional mail can have different statistics from newsletters from marketing mail. Better granularity means that poor senders will be less able to hide behind good senders. I expect to hear some wailing and gnashing of teeth about this change, but as time goes on senders will clean up their stats and their policies and, as a consequence will see their delivery improve everywhere, not just AOL.
Matt has posted a bit more about the SenderScore Blacklist, following up on my post about the changes at Comcast. George Bilbrey, VP and General Manager, for Return Path followed up with him to explain a bit more about the blacklist. George says:
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