3CX Firewall Checker - What 3CX IPs are needed in firewall to pass?

[JLatta]

When my firewall rule is open to ALL, the 3CX Firewall Checker passes with no questions. However, I want to lock down the access to just my VoIP Provider and the 3CX Firewall Checker. What addresses does 3CX use to run the firewall checker because if I remove "ALL" from my firewall rule, it fails.

I see when it runs, it resolves the following:

• stun-us.3cx.com
• stun2.3cx.com
• stun3.3cx.com
• sip-alg-detector.3cx.com

Do those just need to be added in a firewall rule to allow access so the firewall checker will always work with a locked down setup or is there another address 3CX is coming from?

Justin

 

[JLatta]

Nevermind, found other threads after a lengthy search that said the only option was to lock down the firewall rule once you knew it passed to the VoIP providers IPs.

https://www.3cx.com/community/threads/ip-addresses-to-whitelist-for-firewall-check.117117/