You are troubleshooting a Syslog-based single sign-on (SSO) issue on FortiAuthenticator, where user authentication is...

Context: You’re troubleshootingSyslog-based SSOonFortiAuthenticator:

Devices (typically firewalls, WLAN controllers, VPN gateways) sendsyslog messagescontaining usernames, IPs, login/logout events.

FortiAuthenticator parses those logs usingSyslog SSO rulesand injects logon sessions intoFSSOfor FortiGate.

When users are not mapping correctly, you need to see:

Did the syslog message arrive?

Which matching rule (if any) caught it?

What username and IP were extracted?

Why was a message ignored or rejected?

FortiAuthenticator has a dedicated debug area for this:

Debug logs → Single Sign-On → Syslog SSO

This view shows:

Raw syslog lines received

Thematching ruleapplied (or “no match”)

Parsed fields (username, IP, group)

Any parsing errors

This is exactly the tool designed totroubleshoot and diagnose Syslog SSO issues.

Why the other options are not the best for this issue

A. Debug logs > Remote Servers > Syslog Viewer

Lets you see syslog traffic in general, but doesnotshow how SSO rules are applied or why they fail. Good for connectivity checks, not SSO logic.

B. Parsing Test Tool

Useful totestpatterns and rules manually by pasting sample log lines, but it doesn’t show live traffic or running SSO sessions.

C. Debug logs > SSO Sessions page

Shows existing SSO sessions (who is logged in), but notwhya particular syslog message did not create a session.