Sendmail and Comcast
We are running an email server (RH9) using sendmail. After Comcast upgraded / migrated a year or so ago, we started having problems connecting with their email server. As we aren't a Comcast customer, they're not much help and claim they haven't changed anything, yet they admit they just migrated / upgraded all their email servers.
If we send email to a comcast email address, we just get a "connection timed out" error. We seem to function with everyone else.