Skype Screen Sharing fails with Zapp Tunnel mode

My screen sharing start with Zapp in tunnel mode and fails within 3 to 5 seconds stating “There is trouble in sharing”. I suspect whether Zscaler firewall might block and UDP ports. But Screen sharng works fine with Zapp tunnel with local proxy and PAC file.

Hi Ganesh,

Tunnel mode forwards 80/443 traffic through an HTTP Connect tunnel to Zscaler. TwLP mode sends all traffic from the browser & proxy-aware applications to the local proxy (on port 9000) before deciding what to send to Zscaler, so from the sound of it, Screen Sharing is sending traffic on a non-standard port that is being captured by TwLP that isn’t captured via Tunnel.

Out of curiosity, is this Skype for Business or standard consumer Skype?

We use Skype for Business. Doesn’t tunnel mode send everything to Zen. TwLP will sent anything from browser and browser based application to port 9000

Hi Ganesh,

Tunnel mode only sends web traffic on ports 80 and 443. There are plans around the different modes for version 2.0 of the Z App but these are still being tested and no guarantees as to function and/or dates can be given at the moment. (Safe harbour, etc.)

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Hi Thomas,
Appreciate your response. i identified the issue. We use Tunnel mode in trusted network. We were concentrating on PAC in forwarding profile but never thought much about PAC in APP profile. In Tunnel more exception for 443/80 has to be added in APP profile PAC. Once we added Exception in APP profile, our Skype sharing works.

Ganesh krishnan