Comment Smarthost setup (Score 1) 405
I'm in the same boat and I've found that just sending all of my domain's email through Comcast's servers works well enough. I hate doing this on principle, but it has saved me so much hassle that it's not worth fighting.
Depending on your MTA, the configuration will be different, but the arrangement is generally referred to a using a Smart Host. Basically, your MTA directly connects to the ISP's SMTP server and sends the mail from there. Comcast requires authentication to use their servers, but they don't do anything funky to the mail they pass on. All of the headers remain intact except for the DKIM-Signature, which is replaced(?) when Comcast signs the message. I've never had a bounced message that I rerouted through their servers and they support TLS and IPv6, so it's not the worst setup.
I'm sure that if you share your MTA details, someone can help you with the configuration.