Random dropped calls with SBC

[Pascal Lenier]

Hello,

We encounter a random problem of dropped calls.
The problem happends with our only phone connected to the SBC, a Yealink SIP-T58.
There is no problems with Windows Softphones.
There is no problems with Deskphones not compatible with SBC. Those one contacts the PBX directly via VPN.

The calls are drop on random duration, from 20seconds to 30 minutes.
Only notified with external call, both incoming or outcoming.
On the Yealink, the phone return to the homescreen, like if the call was ended by the distant user.
On the distant user's device the call is still going, with no sound of course. It must be manualy close.

The calls appears in the "calls report" as ended by the distant user.

This is the same symptoms as this post :
https://www.3cx.com/community/threads/random-dropped-calls.58431/

I have made a paquet capture on the 3cx PBX during a dropped call, but i don't know how what i must be looking for.

Phone used : Yealink SIP-T58 58.80.0.65
3CX PBX : 15.5.15502.6
SBC on virtual machine

Any ideas?

 

[eddv123]

3CX on virtual machine = you are using the SBC on Windows correct ?

How many endpoint currently use this tunnel ? and if you are running on Windows have you disabled any AV and/or the Windows firewall (if Linux IP tables): https://www.3cx.com/docs/manual/firewall-router-configuration/

 

[cobaltit]

Did you follow the 3CX guide for creating the VM? Is it a supported VM (HyperV, VMWare)?

 

[Pascal Lenier]

Our virtual infrastructure is on VMWare.
The SBC is on debian, installed from the 3CX ISO.
I didn't found the 3CX guide for a WMWare installation, only the HyperV one.

There is only one endpoint using that tunnel, the Yealink that drops the calls.
I am not avaiable today, i will check IPTABLES rules tommorow.

 

[Pascal Lenier]

Here is the iptables INPUT table
We use standard ports (80 443 5060 5090)