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One-Way audio with IP Communicator over VPN


IP Communicator 2.0(2) with CCM 4.1(3)sr2 over VPN connection.

If both sides over VPN connection are IP Communicators, then we experienced one-way audio on the internal side(where CCM located); if internal side is a fixed IP Phone, there is no one-way audio issue.

I know this is a common problem, most likely it related to routing/traffic block issue. But in my case, when internal side, it is a fixed IP Phone, it can work fine.

Any suggestion?



  • Other Collaboration Voice and Video Subjects

Re: One-Way audio with IP Communicator over VPN

Under IPC | Preferences | Audio | Network

Which IP address you are using? If you change it same issue?

The VPN client is a Cisco VPN client?

If not does it creates a Virtual NIC ?

You may gather an sniffer trace to see where we are redirectioning the traffic. For SCCP traffic look for StartMediaTransmission Message

New Member

Re: One-Way audio with IP Communicator over VPN

The customer's VPN Client is CheckPoint.

This is enviroment: IPC 2.0+CUVA 2.0+CCM4.1(3).

When I disabled the CUVA on the both LAN and VPN ends of IPC, then the IPC on the CCM(LAN) side can not hear any audio from the IPC on the VPN Client, but on VPN side, I can hear the audio from the LAN side IPC; If I enabled the CUVA on both sides, then both ends IPCs, sometimes, we can hear each other with Video, and sometime, the LAN side can not hear VPN side with or without video.

Any suggestions?