NetCat help

Hello

I have one question:

how come that when i use command:
netcat -vz localhost 1212
i get
Connection to localhost 1212 port [tcp/lupa] succeeded!
and when i use

netcat -vz 12.12.12.12 1212
i get
netcat: connect to 12.12.12.12 port 1212 (tcp) failed: Connection refused

12.12.12.12 is my IP number of my server

So why this both dont work and my ISP have port open plus i have disable firewall and i use opensuse 13.1 on my server

Tnx

 

on your router, is the port actually forwarded to the right local machine?

 

My server dont have router, plus ISP dont block any port and
firewall i disabled. I am thinking if there is anythink else
if ISP can block port?