Webex Audio Issues with Cloud-Based Secure Client Remote Access VPN

Issue

Users experience no audio or one-way audio in Webex meetings when connected to the cloud-based Secure Client remote access VPN. This issue specifically occurs only when users are connected to the new cloud-based VPN solution, impacting their ability to participate in audio during meetings. The problem manifests as either complete absence of audio or unidirectional audio flow, preventing effective communication during Webex sessions.

Environment

• Technology: Solution Support (SSPT - contract required)
• Sub-technology: Secure Access - Secure Client Remote Access (VPN, Posture, Private Resource)
• Product Family: TAMC
• VPN Type: Cloud-based Secure Client remote access VPN
• Application: Webex meetings
• Issue Scope: Multiple users reporting the same problem

Resolution

• Take packet capture on test user and look for SIP, SDP and RTP traffic.

• In the packet capture, notice that client registration was successful.

• When you look at the RTP traffic, notice that client is sending the RTP traffic towards the server but there is no response.

• After that check on the Secure Access activity search and filter with either client or server IP.

• In the activity search, notice that Firewall as a Service is dropping the traffic since the response from the server would be on a different port which would be considered a new traffic flow.

• Configure an access rule on Secure Access and allow traffic from Server to RAVPN client.

• Additionally, verify the edge Firewall/router configuration and make sure traffic is allowed on the firewall bidirectionally.

Cause

Return traffic flow Server to client was not allowed on Secure Access

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