Other Comcast Customers Cannot Access My Home Server
I am running a small web server (MS/IIS) and RDP terminal for family/hobby purposes and also personal convencience, and I seem to be suffering some kind of intermittent, undiagnosible connection issues.
Up until today, I've had pretty much no issues accessing my web server or RDP from pretty much anywhere. Now, suddenly, tonight, it seems like *specifically* other Comcast customers (e.g., my family from both Mountain View, CA and Atwater, CA) cannot access my Merced, CA server any more. Pinging my domain name from cmd produces the correct Comcast-assigned IPV4 address, but no one with Comcast could communicate with my server on *any* port (80, 443, 8080, my RDP port, nothing).
BUT, it turns out, they *COULD* access my server and all its functionality from smartphone (Verizon/StraightTalk/AT&T) wireless data.
Then, my brother nmap'd my domain name to scan for open ports. The instant he did, suddenly everyone with Comcast was able to communicate with my server again (I was personally at my family in Atwater's house, and confirmed this the very minute my brother told me about it).
What is this all about?