said by AVonGauss:
No, but it is very common for ISPs to require their subscribers to go through their own mail servers or use an alternate port that typically requires authentication to contact remote SMTP servers. This really isn't something new.
As was already mentioned, a business connection from Comcast does not have this restriction or a remote intermediary host or VPS can be used to perform the required tests.
I can do that. I am going to contact them and see what they say tomorrow. It says in the blog post that they will but we will see.