I don't really know how to phrase this better, so I'll just point out what works and what doesnt:
a) I can access my service through 127.0.0.1:port
b) My friend can access my service through x.x.x.x:port where x.x.x.x is my IP (ports forwarded)
c) I, in turn, cannot access my service through x.x.x.x:port
Does anyone know what this may be caused by and how can one fix this?
Best Answer
Look in your router settings for a feature called hairpin NAT or NAT loopback.
In most routers, port forwardings only work from the outside by default, since the actual address translation (NAT) is also done only when packets exit or enter your LAN, not inside the LAN. Enabling NAT loopback should make the forwardings work from the inside too.