Port blocking in Capsule VPN

[xaris222]

Good afternoon.

We have been using Mobile Access for a long time.
Now we have implemented SIP telephony via MAB. Users are connected to the VPN via Capsule Workspace and can make calls to internal numbers. Everything works correctly, ports 10000-20000 are used.

Now we need to configure additional telephony, which works on ports 39960-40000.
The following problem has arisen: we start a call through the application, the call is established, but no voice is heard.
All necessary ports on the gateways are open.

We have performed the following tests:
1. We changed the working ports for SIP telephony to 39960-40000. With Capsule VPN disabled, everything works correctly.
When Capsule VPN is enabled, the following picture is observed:
SIP connection was established between the client device and the server, UDP (RTP) voice packets were sent from the server side to the subscriber device on ports in the range 39960 - 40000, but the subscriber had no voice.

2. also tested the new telephony on ports 10000-20000. Everything works correctly both without Capsule VPN and with Capsule VPN.

We came to the conclusion that Capsule VPN somehow blocks UDP traffic on ports 39960-40000.
Could you please tell me if anyone has encountered such a restriction?