I run my own email server (postfix) and my own DNS servers (bind) on openSUSE 11.2. Lately I've found that I cannot send email to Comcast users, apparently because they cannot do a reverse DNS on my IP address. I do have PTR records set up correctly as far as I know.
I can do a reverse lookup from my local machine with no problem but if I try from outside my network it says the IP address doesn't exist. Is there something else I need to do besides setting up my PTR records to get this to work?