According to the SD-WAN 7.6 Core Administrator study guide and the FortiOS 7.6 Administration Guide, when you are migrating a production FortiGate to use SD-WAN, the most critical step involves reconfiguring how traffic is permitted and routed.

Reference Removal Requirement: Before an interface (such as wan1 or wan2) can be added as an SD-WAN member, it must be " unreferenced " in most parts of the FortiGate configuration. Specifically, if an interface is currently being used in an active Firewall Policy, the system will prevent you from adding it to the SD-WAN bundle.

Firewall Policy Migration (Option A): In a production environment, you must replace the references to the physical interfaces in your firewall policies with the new SD-WAN virtual interface (or an SD-WAN Zone). For example, if your previous policy allowed traffic from internal to wan1, you must update that policy so the Outgoing Interface is now SD-WAN. This allows the SD-WAN engine to take over the traffic and apply its steering rules.

Modern Tools: While this used to be a purely manual process, FortiOS 7.x includes an Interface Migration Wizard (found under Network > Interfaces). This tool automates the " search and replace " function, moving all existing policy and routing references from the physical port to the SD-WAN object to ensure minimal downtime.

Why other options are incorrect:

Option B: While you do need to update your routing (e.g., creating a static route for 0.0.0.0/0 pointing to the SD-WAN interface), the curriculum specifically emphasizes the replacement of references in firewall policies as the primary administrative hurdle, as policies are often more numerous and complex than the single static route required for SD-WAN.

Option C: You do not need to disable the interface. It must be up and configured, just removed from other configuration references so it can be " absorbed " into the SD-WAN bundle.

Option D: SD-WAN is a base feature of FortiOS and does not require a separate license or a reboot to enable.

FortiSASE supports SAML, LDAP, and RADIUS as authentication mechanisms applicable to remote-user identity verification. The FortiSASE Administrator Study Guide explicitly identifies its authentication-server configuration objectives as describing remote authentication with LDAP and RADIUS and SAML single sign-on (SSO). It further states that FortiSASE supports authentication through the local database, RADIUS, LDAP, and SAML for SSO.

SAML (A) provides federated SSO by allowing FortiSASE, acting as the service provider, to rely on an external identity provider for user authentication. SAML SSO is specifically supported for FortiSASE SWG and VPN deployments.

LDAP (C) enables integration with directory services such as Microsoft Active Directory. FortiSASE can query directory information and authenticate users against the LDAP infrastructure; LDAPS can be enabled for protected communications. The guide notes an important limitation: LDAP authentication is unavailable for SIA remote users using IPsec VPN, but LDAP remains a supported FortiSASE authentication source.

RADIUS (E) provides centralized remote authentication and supports PAP, CHAP, MS-CHAP, and MS-CHAPv2 authentication methods.

OIDC and TACACS+ are not identified as FortiSASE remote-user authentication sources in this course objective.

According to the SD-WAN 7.6 Core Administrator study guide and FortiOS 7.6 Administration Guide, the " implicit rule " is the default rule at the bottom of the SD-WAN rule list (ID 0). It is only evaluated if traffic does not match any manually configured SD-WAN rules.

Policy Route Table Context (Option B): SD-WAN rules are technically a specialized form of policy-based routing. For a packet to match the implicit rule, it must first pass through the routing hierarchy. If traffic matches the implicit rule, it indicates that it did not match any higher-priority user-defined SD-WAN rules or any specific entries in the manual policy route table that would have intercepted the traffic earlier.

Session Information (Option E): When you use the CLI to inspect an active session (e.g., diagnose sys session list), the output contains a field for the SD-WAN Service ID. If traffic is steered by a user-defined rule, it displays the ID of that rule (e.g., service_id=1). However, when traffic falls through to the implicit rule, the session information displays no SD-WAN service ID (it often shows as 0 or is omitted), because the implicit rule does not function as a " service " in the same way user-defined rules do.

Routing Behavior: The implicit rule follows the standard routing table (RIB/FIB) logic. It uses the priority and distance of the static routes to determine the path. If multiple paths have the same distance and priority, it uses the algorithm set by v4-ecmp-mode, but this is a function of the routing engine, not the SD-WAN engine itself.

Why other options are incorrect:

Option A: While v4-ecmp-mode (e.g., source-ip-based) is used for ECMP routing, this is part of the general FortiOS routing behavior for equal-cost paths in the FIB, whereas the implicit rule simply " hands over " the decision to that routing table.

Option C: When traffic matches the implicit rule, the session is actually flagged with vwl_id=0 and potentially dirty if a route change occurs, but vwl_default is not the standard flag name used in this specific context in the curriculum.

Option D: This is incorrect because the implicit rule does respect weight, distance, and priority as defined in the static routes within the routing table; it does not distribute traffic " regardless " of these values.