multiple 3CX behind single public IP

[dandenson]

the reasons are many. Office building with multiple tenants. public IP addresses are expensive and the practical maximum on most providers is 5 usable.

I've done my research, I'm looking for reasons this will not be stable.

a) change SIP and tunnel ports for each system.
b) change FIRST/LASTEXTPORT in parameters so each system has a unique set with 4 ports for every external channel.

What would not work or cause issues here?


notes. Cloud hosing ~10 instances adds substantial cost. I already host a number of cloud instances, this question is specifically about multiple systems behind a single WAN IP.

Thanks.

 

[cobaltit]

In theory as long as ports don't overlap then it should be fine but I've never tested it. If it's an office building with multiple tenants then getting a enterprise circuit with enough IPs for all shouldn't be an issue. If you must stick with commodity circuit(s) then there are SDWAN solutions that will give you public IP addresses independent of your connections. But then again if you are looking at commodity circuits just get additional circuits with another block of IPs and call it a day.

I doubt 3CX tests these edge cases and you are looking at an admin headache, especially if/when port ranges change again. At $5/month for Lightsail i see no reason to invite this kind of trouble.