Today, I'm going to practice redis operations and run it on the command line to find the connection unblocked.
Later, it ran with Apache and found that the Redis client (Redis server went away) could not be connected.
By grabbing the packet on the Reids server, it was discovered that Apache was not receiving a connection request at all.
Can know is Apache this side besides problem.
Command line can, Apache under No, my first thought is whether the Apache configuration file restricts a port, the results are not found.
Finally, the answer is found in stackoverflow----that selinux restricts the ports that Apache can open (more specifically, the ports that the HTTP service can open).
Workaround
/usr/sbin/setsebool httpd_can_network_connect=1
Or
Setenforce 0 # #设置SELinux become permissive mode
After mentioning a wake up, in addition to the firewall can stop you, SELinux can stop you, do not forget.
The above describes the Apache PHP can not open the other socket (permission denied) problem resolution, including the aspects of the content, I hope that the PHP tutorial interested in a friend to help.