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:
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.
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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