I'm trying to make a socket connection between a client and my server through a php script. To do this, I opened a port on iptables, and configure a virtual host with apache to redirect all traffic from my door to the folder that contains the file index.php, which is my script. Doing some tests the door is open, but using command netstat -ltn , I see ':::35100'. Looking on the net I understand if in this way is only listen inward and not outward. But I don't understand how can I turn this ':::35100 '-' in this '0.0.0.0:35100 '. Or, better yet, how to add this rule. Any ideas? thanks