The "Master Server" is just server browsing data. it just tells the Game Client "This is a list of servers." the PHP Master Server is not trying to set up a NAT punch through. Just pass information for "You can find a server at 123.123.123.123:5555"

The Game Server is trying to set up a connection. It can hear, but the client can't.


Game Server---> UPnP Router---> Public Cloud <---- NAT Non-UPnP Router <---- Game Client

The client simply needs to connect to the IP/port of the listed server, and no NAT discovery or punch-through is needed.

So then the connection error i'm having is likely in my code and not in a closed client router port?

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EDIT:
it can't be a programing error because any client with UPnP router OR with a client machine directly connected to the internet with no router is able to hear the Game Server say "Yes, you may join the game".

The "Master Server" is just server browsing data. it just tells the Game Client "This is a list of servers." the PHP Master Server is not trying to set up a NAT punch through. Just pass information for "You can find a server at 123.123.123.123:5555"

The Game Server is trying to set up a connection. It can hear, but the client can't.


Game Server---> UPnP Router---> Public Cloud <---- NAT Non-UPnP Router <---- Game Client

The client simply needs to connect to the IP/port of the listed server, and no NAT discovery or punch-through is needed.

So then the connection error i'm having is likely in my code and not in a closed client router port?