The Email Wars

ReturnPath, are you making me fall in love all over again with so many GREAT proactive emails? I know it is close to Valentines Day, so watch out as the love is coming back at you soon…..

Mail Policy Changes at Comcast and Updates on AOL

There are a few new developments regarding Comcast and AOL that we would like to inform you about.

COMCAST
Today Comcast announced that they’ve recently instituted a global throttling policy that rate limits inbound mail to 6 recipients per second from a single IP address, regardless of the number of domains sending from that IP.

If you suspect this is affecting you, look for a 4xx error message (temp-fail) during the SMTP transaction. If the rate-limit is impacting your ability to deliver mail, adjusting your server’s delivery settings to ensure a less than 6 recipient per second rate of delivery should resolve the issue. You can find more detailed information on Comcast’s website.

AOL UPDATES
On Tuesday, AOL announced a few changes to their authentication methods and whitelist program. (go here for the original story). However, there were a few additional notes from AOL’s presentation to the ESPC that we thought you might find interesting.

AOL is providing a tool to test DKIM implementations - We haven’t tested it out yet, but AOL indicated that they were providing a “reflector” to test DKIM implementations. Apparently, if you send a message to [anyaddress]@dkimtest.aol.com, it will generate a bounce message. The bounce message will indicate whether your implementation passed or failed.

There are no changes to the enhanced whitelist for now - As you may know, AOL operates an enhanced whitelist for IP addresses that: (1) are on their regular whitelist and (2) have really, really good reputations. The enhanced whitelist is automatically chosen from the best performing IPs in the “regular” whitelist. The benefits of being on the whitelist are that images and links work by default. AOL indicated that there were no changes.

AOL is providing DKIM results headers - AOL is providing DKIM results (i.e., did you pass?) in the headers of messages. If you are a user of Return Path’s Mailbox Monitor tool, you can view the headers by viewing the message source of messages sent to AOL seeds.

To learn more about DKIM and authentication, sign up for our Quarterly Education Series starting February 12th where you will learn about the benefits of authentication, more about DKIM and how to get started with implementation via a special email series and live webinar. Email editor@returnpath.net with “Sign Me Up” in the subject line.