Always a challenge with an unfamiliar internet setup, i spent several hours trying to get the olduino server on the public internet. AT&T actually has pretty good instructions here but I just could not get it to work when i tried to access the external IP address from my laptop. I could get to the server using the internal lan address but not by going for the external ip address.
It occurred to me to try it from my phone over cellular data and, sure enough, it worked. So something prevents me going over wifi to the public internet and back in through the router. I have always been able to do this before with other routers but I do recall that the connection always looked like it was coming from the gateways itself.
Anyway, I can certainly live with this but it makes testing awkward – I’ll have to go out to the library with my laptop or something – i suppose there might be a telnet app for my phone too so i could try that.