During SSL inspection, if the CN field is used, what is being interpreted?

The correct answer focuses on the interpretation of the CN (Common Name) field within an SSL certificate. The CN field is used primarily to specify the Fully Qualified Domain Name (FQDN) of the server that the certificate is intended to secure. When a client establishes a secure connection to a server via SSL, it checks this field to ensure that the name of the server it’s connecting to matches the CN in the server's certificate. This process is critical in ensuring the identity of the server, thereby helping to prevent man-in-the-middle attacks.

In this context, while the server's cryptographic signature is important for verifying the integrity and authenticity of the certificate, it does not directly relate to the CN field. Similarly, the IP address of the client is not represented in the CN field, nor is it relevant to SSL inspection; this information pertains to the client side of the connection. Additionally, the application layer protocol does not fall under the scope of what the CN pertains to within the context of SSL certificates.

Thus, the interpretation of the CN field as representing the FQDN of the server's certificate is pivotal for establishing secure connections and ensuring reliable SSL inspection processes.