What is external port forwarding?

Issue:
Enter a description of your issue here, in full detail.
I am trying to host a multiplayer room on citra canary build to play with my friend, each one of us is on his own network, and each time he tries to join my room, it tells him that there’s an error and that he should contact the host ( which is me of course ) to check the external port forwarding configuration…
I don’t know what should I fill in the port space in the creating a room box.
PS: I’m using a router.
System Information

  • Operating System: Windows 10
  • CPU:
  • GPU:
  • Citra Version (found in title bar):
  • Game:
  • Screenshot of Issue (include the full Citra window including titlebar):

Diagnostic Log
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https://community.citra-emu.org/t/how-to-upload-the-log-file/296

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citra_log.txt (6.3 KB)

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