As of Version 5, primary publishing and backup agents are hosted, and can be set up in the 2X Console. In the event of a primary failure, the backup agent will take over management of the 2X Client Gateways and 2X Terminal Server agents.
This setup is not enough to provide complete redundancy; if using a single 2X Secure Client Gateway, no users can connect in the case of machine failure.
Within the 2X ApplicationServer client, primary and secondary servers are allowed (input as the IP of the 2X Secure Client Gateways); however, some RDP clients only allow a single name or IP to be referenced. To prevent users from needing to know multiple addresses, users can simply use the DNS Round Robin or Network LoadBalancing (NLB) methods.
In the figure above, we have a 2X Secure Client Gateway hosting our primary Publishing Agent, and a second 2X Secure Client Gateway hosting our backup Publishing agent.
The backup Publishing Agent doesn't operate when the primary Publishing Agent is functioning; however, both 2X Client Gateways are in use, providing redundancy in case of primary Publishing Agent failure and balancing network traffic for clients when both 2X Secure Client Gateways are active.
To Setup DNS Round Robin
1. Add two A (host records); Ex: "clientgateway 192.168.0.2", "clientgateway 192.168.0.3"
2. Set "clientgateway.x.x x.x =" as your dns domain in the client.
DNS Round Robin is explainedin greater detail here: Round Robin DNS.
To Setup Network Load Balancing (NLB)
For setup, NLB protocol must be enabled on network interfaces and assigned a virtual IP address, depending on the version of Windows you are running. Alternatively, hardware loadbalancing (with a Layer 4 switch, for example) can achieve similar results.