Oh wow… Didn't know this lol. I thought that OP would be using their private IP to access their homserver from home. Turns out I got completely confused…
I think if they were using a private IP, there wouldn't really be a joke. Of course the router can resolve an IP in its network. The joke is that they're using their public IP from inside their network, and when the request gets the router, instead of resolving externally, it resolves to the public IP of the router itself.
It's a public IPv4 address in the picture.
There are 3 ranges of IPv4 addresses which are reserved for private use:
24-bit block 10.0.0.0 – 10.255.255.255 20-bit block 172.16.0.0 – 172.31.255.255 16-bit block 192.168.0.0 – 192.168.255.255
Oh wow… Didn't know this lol. I thought that OP would be using their private IP to access their homserver from home. Turns out I got completely confused…
I think if they were using a private IP, there wouldn't really be a joke. Of course the router can resolve an IP in its network. The joke is that they're using their public IP from inside their network, and when the request gets the router, instead of resolving externally, it resolves to the public IP of the router itself.
I changed my local subnet to 10.1.2.0, because it's much easier to type.