[gvb]

My place of business is on Comcast business and we score 10/10 on https://www.mail-tester.com/.

I have problems with several places that firewall the Comcast IPs - Symantec (messagelabs) is the worst because I don't know who uses their services until the message queue backs up and then I have to route around the damage. Really annoying.

To make it worse, I cannot find a way to contact them and ask them politely to whitelist our email server IP address.

Most mail services give a a rejection and, when I've asked to be whitelisted, they do it with no problem (Microsoft, for instance). Symantec simply doesn't respond on port 25 and has no contact information.

It isn't just me: https://www.google.com/search?q=messagelabs+port+blocked