baalexander/node-portscanner — pull request #6 by jdpaton (2012-11-07 20:11:33+00:00)
Title: A function for checking local port availability

This local-only function has the additional check of establishing
a listening socket on the intended port to check availability, which
is destroyed as soon as it is in listening status.

This solved an issue I was having where a port established by SSH was being returned as 'open' by portscanner, i.e:

root 43716 1 0 Nov06 ? 00:00:00 ssh -L 0.0.0.0:35005:192.168.3.218:4101 -f stackato@localhost -N -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no