FCSS_EFW_AD-7.4 Exam Dumps : FCSS - Enterprise Firewall 7.4 Administrator

In the given ADVPN (Auto-Discovery VPN) topology, BGP is being used to dynamically establish routes between spokes. The neighbor-range configuration is crucial for simplifying BGP peer setup by automatically assigning neighbors based on their IP range.

set neighbor-group advpn

● Theneighbor-groupparameter is used to apply pre-defined settings (such as AS number) to dynamically discovered BGP neighbors.

● Theadvpnneighbor-group is already defined in the configuration, and assigning it to the neighbor-range ensures consistent BGP settings for all spoke neighbors.

set prefix 172.16.1.0 255.255.255.0

● This command allowsdynamic BGP peer discoveryby defining a range of potential neighbor IPs (172.16.1.1 - 172.16.1.255).

● Sinceeach spoke has a unique /32 IPwithin this subnet, this ensures that any spoke within the172.16.1.0/24range can automatically establish a BGP session with the hub.

ThisIPsec Phase 1 configurationdefines adynamicVPN tunnel that can accept connections from multiple peers. The settings chosen here suggest a configuration optimized fornetworks with intermittent traffic patternswhile 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→ UsesIKEv2, which is more efficient and supports features like EAP authentication and reduced rekeying overhead.

●set dpd on-idle→ Dead Peer Detection (DPD) is triggeredonly 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 alonger key lifetime(8 hours), reducing the frequency of rekeying, which is beneficial for stable connections.

BecauseDPD 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 fornetworks with regular but non-continuous traffic, balancing security and resource efficiency.

Zero phase selectors inIPsec Phase 2mean thatno specific traffic selectors (subnets) are defined, allowingany traffic to be encryptedthrough the VPN tunnel. This can causeunintended traffic forwarding issuesand disrupt network operations.

To prevent this from happening during future migrations:

●Using routing protocolsensures thatonly specific subnets are advertised over the tunnel. Dynamic routing (such as OSPF or BGP) helps define which networks should use the tunnel, preventing unintended traffic from being encrypted.

●Clearly defining phase 2 selectorsavoids the problem of encrypting all traffic byexplicitly stating the allowed source and destination subnets. This prevents the tunnel from affecting unrelated network traffic.