Linux Virtual Delivery Agent

Rendezvous protocol

In environments that use the Citrix Gateway service, the Rendezvous protocol allows HDX sessions to bypass the Citrix Cloud Connector and connect directly and securely to the Citrix Gateway service.

Requirements:

  • Access to environment using Citrix Workspace and Citrix Gateway service.
  • Control Plane: Citrix Virtual Apps and Desktops Service (Citrix Cloud).
  • Linux VDA Version 2012 or later.
  • Enable the Rendezvous protocol in the Citrix policy. For more information, see Rendezvous protocol policy setting.
  • The VDAs must have access to https://*.nssvc.net, including all subdomains. If you cannot whitelist all subdomains in that manner, use https://*.c.nssvc.net and https://*.g.nssvc.net instead. For more information, see the Internet Connectivity Requirements section of the Citrix Cloud documentation (under Virtual Apps and Desktop service) and the Knowledge Center article CTX270584.
  • Cloud Connectors must obtain the VDAs’ FQDNs when brokering a session. To achieve this goal, enable DNS resolution for the site: Using the Citrix Virtual Apps and Desktops Remote PowerShell SDK, run the command Set-BrokerSite -DnsResolutionEnabled $true. For more information about the Citrix Virtual Apps and Desktops Remote PowerShell SDK, see SDKs and APIs.

Important:

The Rendezvous protocol doesn’t support transparent or explicit proxies. To use proxies, continue to use the Cloud Connector for ICA traffic.

If you enable Rendezvous and the VDA cannot reach the Citrix Gateway service directly, the VDA falls back to proxy the HDX session through the Cloud Connector.

If you meet all requirements, follow these steps to validate if Rendezvous is in use:

  1. Launch a terminal on the VDA.
  2. Run su root -c "/opt/Citrix/VDA/bin/ctxquery -f iuStdP".
  3. The TRANSPORT PROTOCOLS indicates the type of connection:
    • TCP Rendezvous: TCP - SSL - CGP - ICA
    • EDT Rendezvous: UDP - DTLS - CGP - ICA
    • Proxy through Cloud Connector: TCP - CGP - ICA

This diagram is an overview of the Rendezvous connection flow. Follow the steps to understand the flow.

Rendezvous protocol overview

  1. Navigate to Citrix Workspace.
  2. Enter credentials in Citrix Workspace.
  3. If using on-premises Active Directory, the Citrix Virtual Apps and Desktops service authenticates credentials with Active Directory using the Cloud Connector channel.
  4. Citrix Workspace displays enumerated resources from the Citrix Virtual Apps and Desktops service.
  5. Select resources from Citrix Workspace. The Citrix Virtual Apps and Desktops service sends a message to the VDA to prepare for an incoming session.
  6. Citrix Workspace sends an ICA file to the endpoint that contains an STA ticket generated by Citrix Cloud.
  7. The endpoint connects to the Citrix Gateway service, provides the ticket to connect to the VDA, and Citrix Cloud validates the ticket.
  8. The Citrix Gateway service sends connection information to the Cloud Connector. The Cloud Connector determines if the connection is supposed to be a Rendezvous connection and sends the information to the VDA.
  9. The VDA establishes a direct connection to the Citrix Gateway service.
  10. If a direct connection between the VDA and the Citrix Gateway service isn’t possible, the VDA proxies its connection over the Cloud Connector.
  11. The Citrix Gateway service establishes a connection between the endpoint device and the VDA.
  12. The VDA verifies its license with the Citrix Virtual Apps and Desktops service through the Cloud Connector.
  13. The Citrix Virtual Apps and Desktops service sends session policies to the VDA through the Cloud Connector. Those policies are applied.
Rendezvous protocol

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