Added ability to bind to specified network interface with -B
flag.
Usage:
./nc -B tun0 x.x.x.x port
connect using tun0
interface
./nc -B tun0 10.4.24.2 1337
init connection using address 127.0.0.222, port 8080 and bind to lo
interface
./nc -B lo -s 127.0.0.222 -p 8080 127.0.0.1 1337
listen on eth2
interface only
./nc -B eth2 -lv 80