Судя по
Sphere Wiki в sphere.ini нужно прописать внешний IP-адрес, на который подключаются клиенты:
Цитата
//Uncomment next 3 lines below this if you have a router
//First line should be a name different than your shard name above this
//Second line should be your real/external IP (www.whatismyip.com)
//Third line should be the shard port (this should be whatever ServPort is set to)
[SERVERS]
MyShard
127.0.0.1
2593
//External
//my.ip.goes.here
//2593
[EOF]