Which Features Can Be Used?

AD.

Sure, I can explain each of the features and how they can be used to identify users by their client IP address in the context of an upstream and downstream Cisco WSA web proxy.

1. X-Forwarded-For: X-Forwarded-For is a HTTP header that is used to identify the original IP address of a client that is making a request through a proxy server. When a client makes a request through a proxy server, the proxy server replaces the client's IP address with its own IP address. By including the X-Forwarded-For header in the request, the upstream WSA can identify the client's IP address and use it to apply user-based policies or reporting.

2. Via: Via is another HTTP header that can be used to identify the original IP address of a client that is making a request through a proxy server. When a proxy server receives a request, it adds a Via header to the request that includes its own IP address. The downstream WSA can be configured to remove the Via header from the request and forward the request to the upstream WSA. The upstream WSA can then use the IP address included in the Via header to identify the client and apply user-based policies or reporting.

3. High Availability: High availability is a feature that provides redundancy for a WSA deployment. In a high availability configuration, two WSAs are deployed in an active-passive mode, where one WSA is actively processing requests while the other WSA is in standby mode. If the active WSA fails, the standby WSA takes over and starts processing requests. While high availability does not directly provide a way to identify users by their client IP address, it can help ensure that user-based policies and reporting are consistently applied in the event of a WSA failure.

4. Web Cache: Web cache is a feature that allows the WSA to cache frequently accessed web content to improve performance and reduce bandwidth usage. While web caching does not directly provide a way to identify users by their client IP address, it can help improve the accuracy of user-based policies and reporting by reducing the number of requests that need to be processed by the WSAs.

5. IP Spoofing: IP spoofing is a technique where an attacker sends packets with a forged IP address to a network. This technique can be used to bypass security measures that rely on IP addresses for authentication or access control. While IP spoofing does not provide a way to identify users by their client IP address, it can be used to impersonate legitimate users and gain unauthorized access to network resources.

So, the correct answers for this question are A. X-Forwarded-For and D. via, as they are the two features that can be used to identify users by their client IP address when using an upstream and downstream Cisco WSA web proxy.