FCSS_EFW_AD-7.6 Exam Dumps : Fortinet NSE 7 - Enterprise Firewall 7.6 Administrator

When configuring ADVPN (Auto-Discovery VPN) to connect overlay networks across different hubs using IBGP and EBGP, special configurations are required to allow spokes from different overlay networks to dynamically establish tunnels.

● set auto-discovery-crossover enable

● This allows cross-hub tunnel discovery in an ADVPN deployment where multiple hubs are used.

● Since Hub A and Hub B belong to different overlays, enabling crossover discovery ensures that spokes from one overlay can dynamically create direct tunnels to spokes in the other overlay when needed.

● set enforce-multihop enable

● This setting ensures that BGP peers using loopback interfaces can establish connectivity even if they are not directly connected.

● Multihop BGP sessions are required when using loopback addresses as BGP peer sources because the connection might need to traverse multiple routers before reaching the BGP neighbor.

● This is especially useful in ADVPN deployments with multiple hubs, where routes might need to cross from one hub to another.

The OSPF database optimization is necessary to reduce unnecessary routing information and improve network performance. In the given topology, Area 0.0.0.1 is a non-backbone area connected to Area 0.0.0.0 (the backbone area) through an Area Border Router (ABR).

To optimize OSPF in this scenario, configuring Area 0.0.0.1 as a Stub Area will:

● Reduce the size of the OSPF database by preventing external routes (from outside OSPF) from being injected into Area 0.0.0.1.

● Allow only intra-area and inter-area routes, meaning routers in Area 0.0.0.1 will rely on a default route for external destinations.

● Improve convergence time and reduce router processing load since fewer LSAs (Link-State Advertisements) are exchanged.

From the OSPF status output, the key information is:

● "This router is an ASBR" → This means the FortiGate is acting as an Autonomous System Boundary Router (ASBR).

● An ASBR is responsible for injecting external routing information into OSPF from another routing protocol (such as BGP, static routes, or connected networks).