Hi There, we tested a virtual pbx hosted by OVH and this works great. https://www.3cx.com/docs/virtual-pbx-ovh/ Our problem is the firewall on the linux system. In general all ports are open on the VPS server. I try to make a script for iptables and it seemd to work. Calls inbound/outbound, STUN all is working. But the firewall checker does not work. So, i was wondering if anybody has a working script for iptables, where the firewall checker and everything is working. Unfortunately 3CX does not provide a script. Thanks in advance.