Cisco Jabber IM Screen share - port 3389 blocked

[Rich Tuttle]

I wanted to see if anyone had knowledge on if port 3389 is required for Cisco Jabber IM Screen Share. UDP Port 3389 was recently blocked on our Client VPN solution, and we now can't Screen Share via the Cisco Jabber IM method. 

I see that only he port range required for this option is 49152 to 65535. 

Any ideas or thoughts? 

[Jaime Valencia]

Yes, because an IM screen share leverages RDP to work

[Rich Tuttle]

Thanks Jamie. Is there any document that calls out port 3389? I couldn't find it. I reviewed planning and deployment guides. 

We have raised our security level and impacted services. It would be great to reference a document stating it's required. 

[Jaime Valencia]

I don't think it's clearly called out, but this doc states it uses RDP when the feature was introduced:

IM Only Screen Sharing

In addition to the video screen share (BFCP) feature that is available to video-enabled clients when on a call, users can now screen share directly from an IM conversation when video share is not provisioned or available. IM screen sharing uses Microsoft RDP, which is a secure connection. When using IM only screen sharing, the screen share resolution and bandwidth allocations are directly managed by the underlying Windows OS.

https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/jabber/Windows/10_5/rn/JABW_BK_J559CFFB_00_jabber-windows-release-notes-10-5/JABW_BK_J559CFFB_00_jabber-windows-release-notes-10-5_chapter_00.html

[Rich Tuttle]

Any experience with Cisco WebEx Screen Share? This would require moving IM&P function to WebEx Cloud I assume.

But, it sounds like Cisco WebEx Screen Share would enable a better over-all user experience?

[Rich Tuttle]

@Jaime Valencia

Is IM Screen Share ports need to be opened Client to Client? Or Client to Server/Server to Client? 

[jaugello1]

Can anyone help with this issue.  We are using Jabber IM cloud (WebEx messenger) with dual screens on a Windows base PC. When sharing the screen in an IM it defaults to screen 1 only allowing to share that screen not giving an option to select which screen to share. Is there a setting that is required for this option?

Thanks!