I can no longer connect to our Channels DVR server at home from outside our LAN. Used to work flawlessly. All I get is "Your Channels DVR Server At Home Can Not Be Reached".
Other than adding to the never-ending list of abusive Chinese networks and an allow rule so I can communicate with our new Comcast cable modem from the LAN, there've been no changes to the WAN/LAN rules on our Internet border router in years.
From either of my virtual servers out on the 'net I can successfully "telnet host.example.com 8089" There is no special rule in place to allow those virtual hosts in. I have verified, via tcpdump on my Synology NAS, that the telnet connections are indeed forwarded to the NAS upon which the Channels DVR service is running.
tcpdump, running on my border router, does not show any attempt, on the part of anything, to connect to port 8089 when I authenticate that I want to connect the Channels app to my DVR remotely.
I have verified that tcpdump on the router will show attempted, but blocked connection attempts, by running it looking for connections on port 8088, which, like all other ports not explicitly allowed, is denied by default.
Primary Internet connection is Comcast High-Speed Business Internet with a static IP (which has never changed in the eleven years we've had the service). Host has DNS (signed zone) and rDNS.
My conclusion is that, for whatever reason, whatever needs to contact my DVR for the purposes of completing the connection, is not even attempting it.
