got something for you all .. dont found it here.. and maybe it helps:
Solution(s) for Firewall problems (only for Windows Firewall):
1. Close all running Teeworlds things (servers, clients,…)
2. Open start menu
3. Click on “Run … ” (See screenshot in Configuration problems part)
4. Write: “cmd” in there and click ok. !! Administrator rights needed!!
5. Wait till console window opens like this:
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6. “System32” is just the username/working directory -> doesn’t matter.
7. Write: “netsh firewall add portopening UDP 8303 "Teeworlds Client"”
in there and press return.
8. Ignore the long warning message and wait for OK.
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9. That’s it try to play Teeworlds or host a server.
10. If you still got problems maybe you got another firewall (Antivirus, Router, … )
Source: GSGDani's Teeworlds FAQ (not published atm)
© by GSGDani
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