Which mode on the Citrix ADC enables using the client IP address as the source IP for connections to servers?

• A. Layer 2 Mode
• B. USNIP
• C. Layer 3 Mode
• D. USIP

Answer: (D)

Use Source IP (USIP) mode makes the Citrix ADC send connections to backend servers with the original client’s IP address as the source. This allows servers to see the true client IP in logs, apply IP-based policies, and provide accurate analytics, since the traffic appears to originate from the client rather than from the ADC itself.

In practice, when a client with IP X connects to a VIP on the ADC, the ADC forwards the request to the backend with the source IP set to X. For responses to reach the client, there must be proper routing so the network can return traffic to that client IP (or otherwise ensure reachability).

Other modes may use the ADC’s own SNIP or VIP as the source, which means the backend servers see the ADC’s address instead of the client’s. Layer 2 vs Layer 3 modes describe how the ADC participates in the network path, but they do not by themselves guarantee client IP preservation—the USIP option specifically enables it.