I have tried to address this with Comcast security via phone without luck. Being on-hold for an hour to try my luck with different customer service reps is proving frustrating.
I have a situation where Comcast seems to be randomly blocking ingress to my DHCP-assigned address and possibly also doing something weird with Dynamic DNS and I have no idea why. I was hoping someone could tell me exactly what is going on here. Basically I have three issues.
1) I occasionally get Xfinity acceptable use pages injected into my traffic, see attached image. Basically it says that they have an important message for me (presumably some message about what triggered the alert) but there is absolutely no message being sent to me with explanatory data. This has happened maybe 4-5 times. The email it should be using is my actual comcast mail account, which I never use except to get automated messages about usage and bills being paid, etc. I also have a secondary e-mail account on file, but this also doesn't receive any messages (yes, I checked the spam filters). When I called them, after waiting on hold for about an hour for a security person, they couldn't figure anything out and said that I didn't have any warnings on file. Now admittedly I could have violated the AUP unknowingly, I have a family with teenagers. I did on *one* occasion actually get the email, about a year ago, and it was something about downloading an emulator rom I believe.
2) The last two times this happened, within the last 3 months, it appeared that Comcast was messing with my Dynamic DNS (in this case the provider is noip.com). I have a DynDNS updater running on a Synology appliance on the internal network, it is not running on my customer-owned ARIS cable modem. It normally works perfectly. Shortly after getting the AUP notice above, my Dynamic DNS was picking up an IP in the 69.x.x.x range, when clearly my cable modem IP address was something else entirely (73.x.x.x). So my Dynamic DNS agent thinks my IP is 69.x.x.x and "whatsmyip.com" (as well as any system I log into) have the correct IP address. Is Comcast intentionally mangling my Dynamic DNS somehow?
3) I have a couple services running on my home cable modem, NAT'd through a firewall to a VM on a DMZ. Specifically a minecraft server for my kid, and an Apache web server that he uses to practice his programming and do coding schoolwork. The last few times I got the mysterious AUP message above, incoming traffic to my cable modem was blocked on the *correct* cable modem IP. So basically no traffic was allowed in on 80/443/25565. Then after a few hours the message disappears and traffic is allowed again.
So can anyone tell me what is going on here? Is this an automated block intended to stop people from running servers on residential accounts? If so, how does it work and what triggers it? Secondarily, is there anyone I can write a letter to to get myself whitelisted? This is, in all honesty, just set up for people to play minecraft and for coding practice. It is relatively low-bandwidth (except maybe Minecraft) and really annoying, especially since nobody at Comcast can seem to explain it to me. I'm quite willing to do the "correct" thing, if I could only figure out what the heck it was.
Thanks in advance for any help from users or staff that can help shed some light on this situation.