>But then how do we configure Postfix to do this automatically so that >we can gain enough reputation to send more than one recipient at a >time? Because Comcast is not rejecting all mail. Comcast is only >rejecting mail with multiple recipients. Comcast is accepting mail >with single recipients. It's an annoying situation.
Bob, I have the same problem with them. I ran down the lead through their reputation provider, which is mentioned somewhere in their referring URL. I just don't have enough volume to maintain a steady reputation of more than neutral. They (CC) have a table published somewhere that shows the rate they will accept relative to your reputation from the third party reputation company. I lowered how much I push to them at once, and I try to make sure I send to them at least once a month to keep my "reputation" with the 3rd party high enough. My mail probably goes to a few hundred CC recipients. It's a ~3k member opt-in maillist for a racing organization, no ads, no links, clean announcements only, like for race cancellations, or reminders for a race that weekend, rule changes, etc. I used to even send in plain text but read somewhere that was bad and would cause a ding, so I do HTML now. Comcast appears to have washed their hands of it and just puts their full trust in the other company's provided reputation. And the other company isn't counting little guys much. No way to beg for a whitelist I can tell. S
