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.

Use metadata variables to dynamically assign values according to each FortiGate device:Metadata variables in FortiManager allow device-specific configurations to be dynamically assigned without manually configuring each FortiGate. This is especially useful when deploying multiple devices with similar base configurations.

Use provisioning templates and install configuration settings at the device layer:Provisioning templates in FortiManager provide a structured way to configure FortiGate devices. These templates can define interfaces, policies, and settings, ensuring that each device is correctly configured upon deployment.

Add FortiGate devices on FortiManager as model devices, and use ZTP or LTP to connect to FortiGate devices:Zero-Touch Provisioning (ZTP) and Local Touch Provisioning (LTP) help automate the deployment of FortiGate devices. By adding devices as model devices in FortiManager, configurations can be pushed automatically when devices connect for the first time, reducing manual effort.

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.