Unable to forward every port

[logn]

I need to use a remote SSH port forward for every WAN activity due to risks on my end. I have a Proxmox node running two related guests:

CT ws-proxy, runs the vhosts for https://0xlogn.dev and it's sub-domains along with the ssh tunnel
VM for 3CX

What I need is a list of what ports would be used in the FREE 3CX. I know the following list:

UDP/TCP 5060
UDP/TCP 5090
UDP 9000-10999
TCP 5001

On the free version I know I have a call cap, so are the ports allocated in the first available ones? Because two ports per call, does that mean 4 SIM calls = ports 9000-9007?

I also need to somehow SSH forward UDP. Any advice?

0xLogN

 

[Saqqara]

Ports used by 3cx https://www.3cx.com/docs/manual/firewall-router-configuration/

 

[logn]

Ports used by 3cx https://www.3cx.com/docs/manual/firewall-router-configuration/

Great reading.

Port 9000-10999 (inbound, UDP) for RTP (Audio) communications, i.e. the actual call. Each call requires 2 RTP ports, one to control the call and one for the call data, so the number of ports you need to open is double the number of simultaneous calls.

If I have only one call at a time (one SIM call), WIlL IT USE PORT 9000 AND 9001 OR WILL IT CHOOSE RANDOMLY is what my question is. I WILL NOT BE ABLE TO open up 2000 ports. I cannot open one, and SSH is a hack. I will not need 1000 simultaneous calls, nor am I able to on the free version anyway. If I use only 10 calls, can I open ports 9000-9019? That's what I'm asking.

 

[bitn2]

The ports are used randomly.

 

[D Bedford]

It's worth being aware of this page https://www.3cx.com/docs/ which contains a lot of useful guides for setting up and configuring 3CX.
As bitn2 said, the ports used for each call are two (usually adjacent) from the range 9000-10999. If you only open 20 of the ports it's possible that it starts at the beginning of the range so may work initially, then stop working after a couple of calls (with no audio on the call).

The call cap is simply a limit to the number of simultaneous calls that may be made through the PBX.