To allow members of only specific AD groups to participate in FSSO with their corporate FortiGate firewalls, the administrator can configure SSO groups and assign them to FortiGate groups. SSO groups are groups of users or devices that are defined on FortiAuthenticator based on various criteria, such as user group membership, source IP address, MAC address, or device type. FortiGate groups are groups of users or devices that are defined on FortiGate based on various criteria, such as user group membership, firewall policy, or authentication method. By mapping SSO groups to FortiGate groups, the administrator can control which users or devices can access the network resources protected by FortiGate.

The screenshot shows that the account registration feature is enabled for the guest portal and that the guest group is set to Guest_Portal_Users. This means that all guest accounts created using this feature will be placed under that group1. The screenshot also shows that email validation is enabled for the guest portal and that the email validation link expires after 24 hours. This means that all accounts registered through the guest portal must be validated through email within that time frame1.

When deploying FortiAuthenticator for portal services, such as guest portal, sponsor portal, user portal or FortiToken activation portal, the network configuration must allow specific ports to be open between FortiAuthenticator and the authentication clients. These ports are:
TCP 80 for HTTP access
TCP 443 for HTTPS access
TCP 389 for LDAP access
TCP 636 for LDAPS access
UDP 1812 for RADIUS authentication
UDP 1813 for RADIUS accounting

HTTP/HTTPS are the interface services that must be enabled for the SCEP client to connect to FortiAuthenticator. SCEP stands for Simple Certificate Enrollment Protocol, which is a method of requesting and issuing digital certificates over HTTP or HTTPS. FortiAuthenticator supports SCEP as a certificate authority (CA) and can process SCEP requests from SCEP clients. To enable SCEP on FortiAuthenticator, the HTTP or HTTPS service must be enabled on the interface that receives the SCEP requests.

FortiAuthenticator supports various SSO sources that can provide user identity information to other devices in the network, such as FortiGate firewalls or FortiAnalyzer log servers. Some of the supported SSO sources are:
FortiClient SSO Mobility Agent: A software agent that runs on Windows devices and sends user login information to FortiAuthenticator.
FortiGate: A firewall device that can send user login information from various sources, such as FSSO agents, captive portals, VPNs, or LDAP servers, to FortiAuthenticator.
RADIUS accounting: A protocol that can send user login information from RADIUS servers or clients, such as wireless access points or VPN concentrators, to FortiAuthenticator.
SSH sessions and FortiAuthenticator in SAML SP role are not valid SSO sources because they do not provide user identity information to other devices in the network. Reference: https://docs.fortinet.com/document/fortiauthenticator/6.4/administration-guide/372410/single-sign-on