Nodejs Nginx error: (13: Permission denied) while connecting to upstream
By default SELinux only allows the web server to make outbound connections to a limited set of ports.
# semanage port --list
http_port_t tcp 80, 81, 443, 488, 8008, 8009, 8443, 9000
To fix the problem, you simply need to add your own desired port number to the list.
# semanage port --add --type http_port_t --proto tcp 7777
Then you will see the port number added into the list, and your connections should then work.
# semanage port --list
http_port_t tcp 7777, 80, 81, 443, 488, 8008, 8009, 8443, 9000