3CX (Phone System) calls are disconnecting randomly

[Anantheesan]

Dear Community Team,

One of the customer is facing issues on 3CX call system after upgrading to new firewall PA-3220 recently. It was Forcepoint Firewall used by the customer earlier and working fine.

Note: 3CX is a software-based private branch exchange based on the SIP standard.

Setup:- 

• 3CX server has been hosted outside with public IP directly. 
• Users are behind the PA firewall using application to connect 3CX and make and receive calls.
• In PA, Many to one NAT configured to access 3CX server.

Issues:-

• Users are unable to hear the audio from incoming sometime.
• Calls are getting disconnected randomly.

Action:-

• Allowed any application and any ports without any security profiles, but still the issues are occurring.
• Disabled ALG in SIP, but same.

I would need any expert suggestions ASAP.

Thanks

Ananth

[OtakarKlier]

Hello,

If you are decrypting traffic, do not decrypt this traffic. Also on the security policy that is going to the 3CX, dont apply any security profiles.

Regards,

[Anantheesan]

Hi @OtakarKlier ,

Thanks for your comment. BTW, We don't have any decryption policies configured and no security profiles are not configured.

Thanks,

Ananth

[OtakarKlier]

Hello,

Anything in the unified logs that might indicate a reason for the drop/block?

Regards,

[Anantheesan]

Hi @OtakarKlier 

There are no drop/block since allowed any any even no any security profiles.

any idea ??

Thanks,

Ananth

[Anantheesan · Accepted solution]

It was resolved after increasing session timeout in service ports.

Thanks,

Ananth