FCSS_EFW_AD-7.6 Exam Results

In an IBGP (Internal BGP) network, all routers must be fully meshed, meaning every router must establish a BGP session with every other router in the same autonomous system (AS). This does not scale well in large networks due to the exponential increase in BGP sessions.

To optimize and scale IBGP, Route Reflectors (RRs) are used. A Route Reflector (RR) reduces the number of IBGP peer connections by allowing a centralized router (RR) to redistribute IBGP routes to other IBGP peers (called clients). This eliminates the need for a full mesh, significantly reducing BGP session overhead.

By configuring the route-reflector-client setting on IBGP peers, an administrator can:

● Scale IBGP sessions by reducing the number of direct BGP peer connections.

● Optimize the routing table by ensuring routes are efficiently propagated within the IBGP network.

● Eliminate the need for full mesh topology, making IBGP more manageable.

This IPsec Phase 1 configuration defines a dynamic VPN tunnel that can accept connections from multiple peers. The settings chosen here suggest a configuration optimized for networks with intermittent traffic patterns while ensuring resources are used efficiently.

Key configurations and their impact:

● set type dynamic → This allows multiple peers to establish connections dynamically without needing predefined IP addresses.

● set ike-version 2 → Uses IKEv2, which is more efficient and supports features like EAP authentication and reduced rekeying overhead.

● set dpd on-idle → Dead Peer Detection (DPD) is triggered only when the tunnel is idle, reducing unnecessary keep-alive packets and improving resource utilization.

● set add-route enable → FortiGate automatically adds the route to the routing table when the tunnel is established, ensuring connectivity when needed.

● set proposal aes128-sha256 aes256-sha256 → Uses strong encryption and hashing algorithms, ensuring a secure connection.

● set keylife 28800 → Sets a longer key lifetime (8 hours), reducing the frequency of rekeying, which is beneficial for stable connections.

Because DPD is set to on-idle, the tunnel will not constantly send keep-alive messages but will still ensure connectivity when traffic is detected. This makes the configuration ideal for networks with regular but non-continuous traffic, balancing security and resource efficiency.

In a hub-and-spoke topology using OSPF over IPsec VPNs, the point-to-multipoint network type is necessary to establish neighbor adjacencies between the hub and spokes. This network type ensures that OSPF operates correctly without requiring a designated router (DR) and allows dynamic routing updates across the IPsec tunnels.

In this ADVPN (Auto-Discovery VPN) network, there are two hubs (Hub A and Hub B) connected via EBGP, while IBGP is used within each overlay. To ensure proper BGP routing between the overlays, the administrator must configure specific BGP options..

set ebgp-enforce-multihop enable

By default, EBGP requires directly connected neighbors. Since Hub A and Hub B are not directly connected but reach each other over an IPsec tunnel, multihop must be enabled for EBGP sessions to work.

set next-hop-self enable

In IBGP, the next-hop attribute does not change by default. When an IBGP route is advertised from a spoke to another hub or spoke, the next-hop needs to be updated to ensure proper reachability. Enabling next-hop-self forces the BGP speaker to advertise itself as the next-hop, ensuring that all spokes properly reach routes across the overlays.