When FortiAuthenticator is used as anFSSO agentbased onsyslog, it must:

Parse incoming syslog messagesfrom devices (firewalls, WLAN controllers, VPN concentrators, etc.).

Extract identity fieldssuch as:

Username

IP address

Login/logout event indicators

Syslogmatching ruleson FortiAuthenticator define:

Which syslog messages are relevant (by facility, message pattern, or regex).

How to capture specific fields (username, IP, group, event type).

FortiAuthenticator then uses this parsed data toinject logon sessions into FSSO, so FortiGate can apply identity-based policies.

Thus, the role of syslog matching rules is exactly as described inC.

A: Group mapping is handled separately via directory groups / FSSO config, not directly by matching rules.

B: Enforcement of authentication policies is done on FortiGate, not directly by the matching rules.

D: While irrelevant logs can be ignored via rules, the primary purpose isparsing and extraction, not generic filtering.