What information does FortiGate use to identify the hostname of the SSL server during SSL certificate inspection?

The identification of the hostname of the SSL server during SSL certificate inspection primarily relies on the server name indication (SNI) extension found in the client hello message. SNI is an extension to the SSL/TLS protocols that allows the client to specify the hostname they are trying to connect to at the start of the handshake process. This is particularly useful in shared hosting environments where multiple domains are served from a single IP address.

By examining the SNI, FortiGate can determine which hostname the client is attempting to reach, which is essential for SSL inspection because it allows the firewall to present the correct certificate and correctly validate the connection. This is crucial for ensuring that secure connections are appropriately filtered and monitored.

Other options, while related to SSL connections, do not provide the hostname information needed for this process. The subject field in the user access request pertains more to the identity of the user rather than the server. The SSL version and cipher suite relate to the protocol and encryption methods being used but do not contain hostname information. Thus, the SNI extension is the vital piece of information used in identifying the hostname during SSL certificate inspection.