Sophos xgs 2100 one way audio when I connect to IPsec VPN and use internal gateway VoIP

Hi Administrator User635

Please try to add your voice server IP through snat and check 

1. On the CLI, enter 4 for Device console.

2. Add an IPsec route from the branch office firewall to the Voice server in the head office. Enter the following:

   system ipsec_route add host <IP address of host> tunnelname <tunnel>

   Example

   system ipsec_route add host 172.16.16.17 tunnelname BO_to_HO

3. Translate the IP address of the LAN port (Voice interface) of the branch office firewall to the Voice server's IP address at the head office. You must use this command to translate traffic generated by Sophos Firewall. Enter the following:

   set advanced-firewall sys-traffic-nat add destination <Destination IP address or network> snatip <Source IP address to translate>

   Example

   set advanced-firewall sys-traffic-nat add destination 172.16.16.17 snatip 10.10.1.1

   here 172.16.16.17  is voice server IP and 10.10.1.1 is LAN IP at BO