Why is "nc -l xxxx" not opening a port?

Solution 1:

I ran the verbose mode -v and got a clue back:

4444: inverse host lookup failed: Unknown server error : Connection timed out`
listening on [any] 41579 ...`

so I tried specifying a port with -p like this nc -lvp 4444 and it works:

listening on [any] 4444 ...

Obviously I need to use -p with -l with this version of nc.

I'd love it if anyone could tell my why there is this difference. Am I running an old version? (-h reports v1.10-38)