I have a problem with jabber clients. Jabber to Cisco IP phone and Jabber to Jabber calls work fine within our LAN.
The problem is when someone from outside the LAN trying to use Jabber over VPN connection we encountered these symptoms :
1- When the call is between 2 IPhone clients or an IPhone and cisco IP phone everything works just finee .
2- when one of the 2 call parties or both are android or pc ==> the call is successful " meaning: the caller can ring the receiver " but when the receiving party answer the call there's no voice and they can't hear each other
What approach should i take to solve this problem ?.. could it be a firewall-related issue or NAT issue ?
we are using Microsoft TMG firewall,, everything was working just fine but suddenly some calls have no audio and this problem happens only when using jabber clients on android or windows over vpn connection
There needs to be a NAT rule in your VPN connection that allows connectivity between the connected clients. Otherwise they will experience this audio issue. You didn't specify the type of VPN equipment your were using. Had this same issue with my ASA and Anyconnect clients when connected. Resolved with a NAT rule in the ASA firewall configuration section. Can't say why android is affected though, I only had this issue with connected PC's and their local Jabber client.