I’m not going to argue with you about it other than to say I’m the one that has been using them for years and all has been good for the most part. As for the issue I’m willing to bet it’s the latest firmware update that’s the problem. I know they did a firmware update within the last 3 or 4 months cause their port forwarding section is setup now by device connected instead of covering all connected devices with one setting.
In the end the comcast/xfinity router was indeed the issue?
Glad it got sorted. Its cheaper to buy your own anyways - and you get a lot more control with nicer firmware (even if you dont flash your own). 
The point was and still is that the service from Xfinity over all is very good. Can’t chastise them for one bad firmware update.
I though the point was ascertaining what the problem was.
Which was apparently the router.
It is still somewhat odd to be so protective of this particular multi billion dollar company. One that does not even have a very good reputation outside of this discussion. But you are of course free to love comcast as much as you like.
I stand by what I said and this conversation is now done.
Problem was router.
No bull about it.
I still do not understand what is so upsetting about pointing it out.
You have even confirmed it yourself.
It seems the original comment was now changed from calling it “BS” to “I stand by what I said”. Le sigh.
End it NOW.
Excuse you?
Anyways I have marked the first comment pointing out the xfinity hardware as the solution. Because you have admitted that changing from their supplied router fixed the issue.