Hello,
=>
https://www.managames.com/tennis/doc/Te ... ml#networkthen =>
topic8-3102.phpIn short, the main advices are :
- try the UDP Port 80 instead of 4321 ; or try the UDP Port 54321 instead of 4321
- turn off your Firewall
- set your router to "Forward all", or set your PC to DMZ (be sure you don't have security issue on your PC if you do that) ; if not better, try Bridge mode instead of Router mode (if your Router has a Bridge mode)
- check your Windows Network is a "Private network", not "Public Network" (Tutorial =>
http://www.opentechguides.com/how-to/ar ... -type.html ) ; or try to allow TE2013 in Windows Firewall even on Public network.
Update December 2020 :if you don't have a public IPv4 (ie: either no IPv4 from your ISP at all, or a private IPv4 encapsulated within IPv4 or IPv6 at your ISP level), then you won't be able to be joined by people using the server list.
You should still be able to be joined by providing your IPv6 to another player, which he should enter in the "Join Remote Game" IP. (I might have tested that a decade ago, so I'm not sure it's still working

)
Update March 2022 :If you're behind a
CGNat, you'll never be able to host.