Hi, This is for me the first time I have install Debian with the ISO provided by 3CX. All went well but I want to use a other listen port, not 5060. But after change this port in 3CX, reboot the system the firewall checker failed. It expect that port 5060 is open, but this is a other port. I have read that something has to be changed in iptables(?), but I don’t know how or where I can find this table. All ports can be left as default, except port 5060. For me Windows is no problem, but Linux is a different story. Hope somebody can advise me how to do this. Thanks for the help.