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.
I’ve been hearing rumors that some *.rr.com domains have been bouncing all mail sent to them. Those domains belong to customers that were moved to Comcast as part of the RoadRunner / Comcast / Adelphia purchase and customer swap. As a courtesy, RoadRunner forwarded mail to comcast for those former RoadRunner customers, but have ceased to do so.
Mail to any address in the following *.rr.com domains will no longer be delivered.
jam.rr.com
midsouth.rr.com
mn.rr.com
se.rr.com
sport.rr.com
swfla.rr.com
ucwphilly.rr.com
houston.rr.com
These addresses should be removed from your lists. These users now have Comcast addresses. You cannot just substitute the Comcast domain for the RoadRunner domain as users were required to choose new localparts. That means bobjones@houston.rr.com may not be, and probably is not, bobjones@comcast.
A few days ago I posted about Yahoo using the Spamhaus lists. In the comments of that post there have been multiple reports of mail being bounced from Yahoo with a reason of “on the PBL” but the IP was not on the PBL.
I am happy to look into this for people. I’m sure neither Spamhaus nor Yahoo want to be incorrectly rejecting email. To do this, though, I need the rejection message from Yahoo, the IP the mail was sent from and when it happened. Feel free to email the information to laura at wordtothewise.com.
A couple articles came out today talking about ISP requirements and how to find them.
EmailInsider talks about ISP best practices and how merely complying with CAN-SPAM is not enough to get good delivery at the ISPs.
Meanwhile, over at ClickZ, Stefan talks about what the ISPs want from you and how to find the information online.