Solved 3CX Firewall Checker

[E.Nunn]

Hi,

I have an issue where the firewall is showing as all ports closed. I have a static IP (not being cgnatted, been there fixed that), I've tested the ports from an outside port checker on a 4G phone which works fine, but it's still giving me every error it possibly can as shown in the attached log.

The even stranger part about this is that I can make and receive calls just fine through the 3CX android app over the mobile network data.

Any help is much appreciated.

Edward

 

[SteveITS]

Is there security on the router which is blocking the test as a port scan?

 

[E.Nunn]

Is there security on the router which is blocking the test as a port scan?

Well thanks, it would appear that pfSense needs specific rules to keep ports static. Very strange...

 

[SteveITS]

Ah, the router was going to be my next question. Yes pfSense randomizes those.
https://docs.netgate.com/pfsense/en/latest/nat/outbound.html#static-port

 

[Saqqara]

Setup instructions for pfsense https://www.3cx.com/docs/pfsense-firewall/

 

[ChrisC_3CX]

I do want to mention that the fact that it works is not surprising as the only issue here seems to be port preservation which may or may not cause issues depending on the situation. To confirm have you managed to prevent port remapping on your firewall and if yes, what did you need to do?

 

[E.Nunn]

To preserve ports on pfSense I just followed the guide linked above. It turned out that having Full Cone NAT / Port Preservation disabled was the problem. Before SteveITS told me of the potential issue, I wasn't aware that it differed from firewall to firewall.

 

[ChrisC_3CX]

Oh I see, for some reason I was under the impression you had to take extra steps than those mentioned in the guide. Thank you for clarifying!