Port 25 (SMTP) Is Blocked. How can I get it unblocked?

Well, that was utterly unhelpful. The first battle in speaking with the tech support technician was getting them to understand that I was saying *PORT* 25 and not 425. Once we got through that, they insisted I was referring to Xfinity email. I had to explain to them, that I am trying to set up an email *server*, not *connecting* to a 3rd party email server. They then wanted to troubleshoot my WiFi. Another barrier to get through. I explained to them, that this is not a wireless issue. Once we got through that, they wanted to reset my modem to see if it would start working. I had to explain that this is not an issue in my internal network as I have already tested that it all functions in my network, and that the problem was on the Xfinity network blocking the port. They still did not understand and just wanted to read a security vulnerability article to me. Long story short, I was told I needed to be transferred to the Security department, but that they are closed (surprise). I have a suspicion that this will yield no fruit, but if I don't get a response here, I will try it tomorrow. 

I am honestly surprised at how little they understand basic networking. In the most basic sense, there are two side to every customers network. There is from the modem to the user (the local LAN/WiFi), then there is the Internet side (in this case, the Xfinity side). I get it, they have a checklist to go through and an internal knowledge base to search, but a small fundamental understanding of networking would go a very long way. 

Has anyone else been successful in getting this through through to the standard Tech Support folks?  My apologies for this turning into a rant. I hope that anyone reading this, has a great 4th of July. 

Concern moved here to the E-mail help section for assistance.

... I am trying to set up an email *server* ...

Note that Comcast's Internet AUP ( https://www.xfinity.com/Corporate/Customers/Policies/HighSpeedInternetAUP ) states:

... prohibited uses and activities include ... using the Service ... to ...

• use or run dedicated, stand-alone equipment or servers from the Premises that provide network content or any other services to anyone outside of your Premises local area network (“Premises LAN”), also commonly referred to as public services or servers. Examples of prohibited equipment and servers include, but are not limited to, email, web hosting, file sharing, and proxy services and servers;

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@BruceW I get what you're saying, but this is not for use by anyone, and is only for my testing purposes. That is all. No real email is hosted on it for anyone. Unfortunately, I can't validate its functionality without port25.