Hi all,

I have an Samsung Mobile, running latest Jabber for Android (version 11.8.0.249427), connected with WiFi Network.  It can access Internet via Firewall, with normal & standard NAT operation.  I can register the Jabber client to the CUCM (11.5) in another site via Internet and Expressway (x8.8).  But when I try to make call, there is one-way audio.  Remote party can hear me, but I can hear nothing at the Jabber client.

I've checked Firewall settings & logs, Expressway settings & debug logs, and finally, wireshark capture at my local Network.  I found that, when my Jabber client is communicating with the Expressway & CUCM for signalling (TCP 8443, TCP 5222, ...), it is sending from the Mobile's local IP Address (192.168.18.164); but when it start the media traffic (UDP traffic), it use an unknown IP Address (10.219.99.152) as the source IP.  As a result, when the remote Expressway return traffic to my Firewall, it translate to this unknown IP Address, and no one can receive it.

If my Mobile is connected to Internet directly (via 4G), it's totally OK.  No one-way audio problem.

I try to use my friend's iPhone with Jabber for iPhone 11.7.2.247543, it's also totally OK.

I also try another Android mobile with Jabber for Android 11.7.2.248180, it's totally OK as well.  (But I cannot install J4A 11.7.2 apk to my Samsung Mobile for testing.)

Have anyone tried something similar?  Is it a bug in J4A 11.8.2?  Any solution?

Best Regards,

Enoch TSE