Socat - nifty tool ;)

Here's some tips to test "socat"

: connect to port 80
> socat - tcp4-connect:192.168.1.1:80
-----------------------------------------------------------

: connect to port 80 + verbose
> socat -d -d - tcp4-connect:192.168.1.1:80
-----------------------------------------------------------

: listen to port 80
> socat -d -d - tcp4-listen:80
-----------------------------------------------------------

: Port forward : listen on port 443 -> send to 80 of the host
> socat -d -d tcp4-listen:443 tcp4:192.168.1.1:80
-----------------------------------------------------------

There's lot's more, try socat -h
.

examples:
http://technostuff.blogspot.com/2008/10/some-useful-socat-commands.html