Random call drop and poor quality on 3CX app behind Sophos XG

[GrosDoux]

Hi all,

We currently have different problem using Softphone app and desktop (v18) /webclient app on a network behind a sophos XG. Randomly, we have calls drop, one-way audio, can't answer incoming call or poor quality communication
All seems fine from another location (not behind this Sophos)

All UTM Profil seem to be disable on the firewall (we only have read only access on him, it's not our equipement)
udp-timeout-stream is set to 300 seconds
SIP-ALG is disable
Our 3CX server is located on Amazon AWS Paris

That's the only server where we have this problem, and it's also the only one on our park with a Sophos firewall between the softphone and the cloud server.

What can we check or adjust on the Sophos to make 3CX work correctly ?

Thanks !

 

[OlegR_3CX]

Hi there.
So if you connect another devices that are behind different firewall, let's say mobile devices via DATA network, no issue at all?

 

[GrosDoux]

Hi,

Yes behind different firewall (Fortinet) we don't have any issue

 

[OlegR_3CX]

So if you allow and not filter the traffic from that site to the IP of the 3CX server, and by pass all your firewall rules there, does it resolve your issue?
Based on your explanation it is network related, and seems your firewall does something differently there.

 

[GrosDoux]

Nop, the problem persist with no filter from/to 3CX server

Yes that's what i think too but i don't really know what can be the problem.

I tried to change udp-timeout-stream which can cause some problem (i found it on several forum with 3CX behind Sophos) but there's no change after that
Maybe spicific Sophos settings

 

[OlegR_3CX]

What Sophos support advise there, did they give you any feedback?

 

[OlegR_3CX]

Have you also tried using 3CX hosted/SMB and connect new device that are behind the same firewall and see how it goes and if you face the same issue?
Also in V20 you have a feature for the call quality where you can see basic info on the packet loss, jitter etc
Since you can have it as a trial for some time, give that a go and see how it goes so you can eliminate the issue between ISP and cloud there too.