Quote from: RobinMa on December 28, 2014, 02:09:48 PM
... Must I deacticate the windows firewall?
No, but you have to create a rule to allow the communication for "kart.exe".
For a quick test disable the firewall and and check the ping of your server. If you get ping, enable the firewall again and follow one of these tutorials:
http://www.howtogeek.com/112564/how-to-create-advanced-firewall-rules-in-the-windows-firewall/
http://www.technipages.com/blockunblock-programs-in-windows-firewall
If you didn't get ping when the firewall was disabled then you should look at your antivirus. Often security suites disable the windows-firewall and use their own firewall instead.
Looking at your picture from yesterday, the port forwarding in your router seems to be ok.