After having successfully installed PortSIP PBX, the PortSIP PBX ports have been opened with the Linux firewall. Note, PortSIP PBX enabled the firewalld by default, if you using Debian/Ubuntu, the UFW will be disabled automatically by PortSIP PBX. If your server has a firewall that is blocking the ports, you must open the below ports in order to make the PortSIP PBX working properly.