My tests on IRC blocking in 6in4 tunnel
I was helping to test goIPv6 tunnel (6in4 tunnel) which will be officially launched on 11 July 2013. There are two security precautions imposed by the tunnel provider, namely blocking of SMTP and IRC connections. This is quite understandable as malware infected PCs can send out spam and communicate with botnet command control centre through IRC port 6667 to launch malicious attacks. Wait, I did not have IRC daemon. How could I test it. I recalled that I could make use of netcat (nc) as follows:
Server side (listening mode ) : #nc -6 2401:300:0:1::8080 -l 6667
Win 7 Client side (transmit mode): c:\nc6 2401:300:0:1::8080 6667 –n –v
In the client side, nc6 for Windows 7 should be used which supports IPv6. If connection could be put through, key inputs from the client side will be echoed in the server side.
Hopefully, the blocking test was conducted successfully.