Now I want to share this is centos 7 firewall issue. Sometime firewall not installed or service not running on your centos 7 server. So you can’t allow any port from your server. Error below when your run command for allow port.

$ [[email protected] ~]# firewall-cmd --zone=public --add-port=80/tcp --permanent

FirewallD is not running

$ [[email protected] ~]# systemctl start firewalld
$ [[email protected] ~]# firewall-cmd --reload
success

Now check status using below command

$ [[email protected] ~]# systemctl status firewalld

● firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
Active: active (running) since Wed 2019-08-28 17:27:41 UTC; 18s ago
Docs: man:firewalld(1)
Main PID: 13581 (firewalld)
CGroup: /system.slice/firewalld.service
└─13581 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid

Aug 28 17:27:41 asterisk systemd[1]: Starting firewalld - dynamic firewall daemon...
Aug 28 17:27:41 asterisk systemd[1]: Started firewalld - dynamic firewall daemon.

Allow voip port for PBX SIP and IAX Communication from centos 7 server.

$ [[email protected] ~]# firewall-cmd --zone=public --add-port=5060/udp --permanent
$ [[email protected] ~]# firewall-cmd --zone=public --add-port=5061/udp --permanent
$ [[email protected] ~]# firewall-cmd --zone=public --add-port=5160/udp --permanent
$ [[email protected] ~]# firewall-cmd --zone=public --add-port=5161/udp --permanent
$ [[email protected] ~]# firewall-cmd --zone=public --add-port=10000-20000/udp --permanent
$ [[email protected] ~]# firewall-cmd --zone=public --add-port=4569/udp --permanent
$ [[email protected] ~]# firewall-cmd --zone=public --add-port=5160/tcp --permanent
$ [[email protected] ~]# firewall-cmd --zone=public --add-port=5060/tcp --permanent
$ [[email protected] ~]# firewall-cmd --reload
success

Now check all enable allow ports using below command.

$ [[email protected] ~]# firewall-cmd --list-all

Output as like below

public
  target: default
  icmp-block-inversion: no
  interfaces:
  sources:
  services: ssh dhcpv6-client
  ports: 80/tcp 5060/udp 5061/udp 5160/udp 5161/udp 10000-20000/udp 5160/tcp 5060/tcp
  protocols:
  masquerade: no
  forward-ports:
  source-ports:
  icmp-blocks:
  rich rules:

Allow voip port for PBX User Control Panel (UCP) from centos 7 server.

$ [[email protected] ~]# firewall-cmd --zone=public --add-port=81/tcp --permanent
$ [[email protected] ~]# firewall-cmd --zone=public --add-port=4443/tcp --permanent
$ [[email protected] ~]# firewall-cmd --zone=public --add-port=8088/tcp --permanent
$ [[email protected] ~]# firewall-cmd --zone=public --add-port=8089/tcp --permanent
$ [[email protected] ~]# firewall-cmd --zone=public --add-port=8001/tcp --permanent
$ [[email protected] ~]# firewall-cmd --zone=public --add-port=8003/tcp --permanent
$ [[email protected] ~]# firewall-cmd --reload
success

For more FreePBX official site.