I wrote a simple tcp/ip chat and it worked with the localhost IP(127.0.0.1) as well as connecting to another computer on the local network. Through the Internet (v4 IP address) it didn't work so I tried the codeproject example:
I downloaded but it threw the same exception on connecting:
TcpClient Client = New TcpClient(IPAddr, 65535);
I tried with another port and turned off Windows-Firewall and Avira-Free.
Update: If I connect to another Internet IP address, the following exception is thrown:
A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond IP-Address: 65535