Two customers hearing other conversations during the call

[Shobosh]

Two of my customers (hosted PBX) are complaining of hearing other conversations during calls. This is happening extension to extension as well as external calls.

Both customers are using 3CX hosted PBX (separate instances) on Version 18.

Both customers have been using their systems for over a year without any recent changes. Suddenly this is happening today.

I have no idea as to how I might fault find / diagnose the issue.

Grateful for all and any thoughts please.

Thank you,

Shobosh

 

[leejor]

How are the extensions set up? Behind an SBC, STUN? Are they able to identify who is having the other conversations? One other extension, or multiple extensions?
Is this happening during both incoming and outgoing calls?
How many extensions is this happening to?

 

[Shobosh]

How are the extensions set up? Behind an SBC, STUN? Are they able to identify who is having the other conversations? One other extension, or multiple extensions?
Is this happening during both incoming and outgoing calls?
How many extensions is this happening to?

Hi Leejor,

How are the extensions set up (STUN or SBC)?
>>> A mixture. However, customers report the issue on both STUN and SBC.
>>> The environment is Yealink W60B (firmware as recommended by 3CX/Yealink) and Yealink W56H DECT handsets.

Are they able to identify who is having the other conversations?
>>> No, not within company. I'm told it's like being in a conference call, with uninvited guests !

One other extension, or multiple extensions?
>>> Multiple extensions.

Is this happening during both incoming and outgoing calls?
>>> Yes. Both.

How many extensions is this happening to?
>>> All extensions.

>>> Tricky one huh? Kinda difficult to diagnose.

>>> Thanks for your input/contribution.

>>> Shobosh

 

[JohnS_3CX]

Hello,

Both customers have been using their systems for over a year without any recent changes. Suddenly this is happening today.

STUN has a "habit" of working fine for a while, then suddenly problems appear out of nowhere. This issue can happen when the audio packets meant for one device, are delivered to another device. Most often you will find this happening in STUN where ther port forwards were not set up properly, and your firewall is not able to properly identify where the traffic should go and ends up delivering them to the wrong device or wrong port.

The solution here is to remove STUN phones entirely, move everything to the SBC, and factory reset and reprovision your devices as per our guides. This should ensure that neither internal or external calls have crosstalk.

The SBC must absolutely be on the same network as the phones, don't put them in different VLANs or subnets to each other.

This in 99% a networking issue based on your description, some good practices should be able to resolve this: if your two customers hear each other, make sure they are not on the same network (ie. if they share an office space, give them different subnets). Each one should have their own network, own SBC, own PBX.

 

[Shobosh]

Hello,

STUN has a "habit" of working fine for a while, then suddenly problems appear out of nowhere. This issue can happen when the audio packets meant for one device, are delivered to another device. Most often you will find this happening in STUN where ther port forwards were not set up properly, and your firewall is not able to properly identify where the traffic should go and ends up delivering them to the wrong device or wrong port.

The solution here is to remove STUN phones entirely, move everything to the SBC, and factory reset and reprovision your devices as per our guides. This should ensure that neither internal or external calls have crosstalk.

The SBC must absolutely be on the same network as the phones, don't put them in different VLANs or subnets to each other.

This in 99% a networking issue based on your description, some good practices should be able to resolve this: if your two customers hear each other, make sure they are not on the same network (ie. if they share an office space, give them different subnets). Each one should have their own network, own SBC, own PBX.

Thanks JohnS_3CX,

That makes perfect sense.

I will make sure all extensions are serviced via SBC.

Assume all is well unless I report back

Much obliged,

Shobosh