A TCP/IP network connection may be either blocked, dropped, open, or filtered. These actions are generally controlled by the IPtables firewall the system uses and is independent of any process or program that may be listening on a network port. This post will outline the steps to open a port required by a application.
Use this command to find your active zone(s):
It will say either public, dmz, or something else. You should only apply to the zones required.
In the case of dmz use:
As example we use port 2888.
firewall-cmd –zone=dmz –add-port=2888/tcp –permanent
firewall-cmd –zone=dmz –add-port=2888/udp –permanent
Otherwise, substitute dmz for your zone, for example, if your zone is public:
firewall-cmd –zone=public –add-port=2888/tcp –permanent
firewall-cmd –zone=public –add-port=2888/udp –permanent
Then remember to reload the firewall for changes to take effect.
Impact colateralAlso you need to forward those ports on your network router.
Plan de restaurare in caz de nefunctionare
A good ideea would be to have a copy of CentOS on external hard drive or usb stick.