Fortinet FCSS_EFW_AD-7.4 - FCSS - Enterprise Firewall 7.4 Administrator

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.

TheInternet Service Database (ISDB)in FortiGate is used to enforce content filtering atLayer 3 (Network Layer) and Layer 4 (Transport Layer)of the OSI model by identifying applications based on theirpredefined IP addresses and ports.

FortiGate has a predefined list of all IPs and ports for specific applications downloaded from FortiGuard:

● FortiGate retrieves and updates apredefined listof IPs and ports for different internet services fromFortiGuard.

● This allows FortiGate to block specific services atLayer 3 and Layer 4without requiring deep packet inspection.

The ISDB blocks the IP addresses and ports of an application predefined by FortiGuard:

● ISDB works by matching traffic to knownIP addresses and portsof categorized services.

● When an application or service is blocked, FortiGate prevents communication bydenying traffic based on its destination IP and port number.

When FortiGate is operating inproxy modewithfull SSL inspection enabled, it inspects encrypted HTTPS traffic by default onport 443. However, some websites may usenon-standard HTTPS ports(such as 8443), which FortiGate does not inspect unless explicitly configured.

To ensure that FortiGate inspects HTTPS traffic onport 8443, administrators mustmanually add port 8443in theProtocol Port Mappingsection of theSSL/SSH Inspection Profile. This allows FortiGate to treat HTTPS traffic on port 8443 the same as traffic on port 443, enabling proper inspection and enforcement ofFortiGuard category-based web filtering.

The output of the get router info ospf status command provides key information about the OSPF (Open Shortest Path First) configuration on the FortiGate device.

The FortiGate device is connected to multiple areas

● The output states: "This router is an ABR"

●ABR (Area Border Router)means the device is connected tomultiple OSPF areasand maintains routing information between them.

● This confirms that the FortiGate isnot just in one area, but at leastone backbone area (Area 0) and another OSPF area.

The FortiGate device injects external routing information

● The output states: "Supports opaque LSA"

●Opaque LSAs(Type 9, 10, and 11) are used inOSPF extensions, including those that support external route injection.

● Typically, ABRs or ASBRs (Autonomous System Boundary Routers)inject external routes, allowing routes fromother routing protocols (such as BGP or static routes) to be advertised into OSPF.

When FortiGate processes the first packets of a session, it follows a sequence of steps to determine how the traffic should be handled before establishing a session. The initial step involves:

● Access Control List (ACL) checks: Determines if the traffic should be allowed or blocked based on predefined security rules.

● Hardware Packet Engine (HPE) inspections: Ensures that packet headers are valid and comply with protocol standards.

● IP Integrity Header Checking: Verifies if the IP headers are intact and not malformed or spoofed.

Once these security inspections are completed and the session is validated, FortiGate then installs the session in hardware (if offloading is enabled) or processes it in software.

The diagram shows a FortiGate connected to two FortiSwitches, which suggests the use ofFortiLink, Fortinet's protocol for managing switches directly from a FortiGate. Since multiple connections are being used, the LAN interface must be set to802.3ad (LAG)mode to aggregate the links for redundancy and load balancing.

This setup allows FortiGate to handle VLAN assignments dynamically, as seen withVLAN 10 (192.168.15.1/24). FortiLink ensures seamless integration between FortiGate and FortiSwitches, making STP unnecessary because Fortinet'sMCLAGprevents loops at Layer 2. SD-WAN, on the other hand, is used for WAN interfaces and does not apply to switch connectivity in this scenario.

In atransparent mode Virtual Domain (VDOM)configuration, FortiGate operates as aLayer 2 bridgerather than performing Layer 3 routing. Theset forward-domain <domain_ID>command is used to control how traffic is forwarded between interfaces within the sametransparent VDOM.

Aforward-domainacts as abroadcast domain, meaning only interfaces with thesame forward-domain IDcan exchange traffic. This setting is commonly used toseparate different VLANs or network segmentswithin the transparent VDOM while still allowing FortiGate to apply security policies.

InBGP (Border Gateway Protocol), aneighbor (peer) configurationis required to establish a connection between two BGP routers. SinceFortiGate A is connecting to the ISP (Autonomous System 10) from AS 30, the administrator must define theISP's BGP router as a neighbor.

Theconfig neighborcommand is used to:

●Define the ISP's IP address as a BGP peer

●Specify the remote AS (AS 10 in this case)

●Allow BGP route exchanges between FortiGate A and the ISP

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.