Pass the Fortinet Fortinet Certified Professional Network Security FCSS_EFW_AD-7.6 Questions and answers with CertsForce

The set tcp-mss-sender and set tcp-mss-receiver commands in a firewall policy allow an administrator to adjust the Maximum Segment Size (MSS) of TCP packets.

This setting controls the largest payload size that a device can handle in a single TCP segment, ensuring that packets do not exceed the allowed MTU (Maximum Transmission Unit) along the network path.

● set tcp-mss-sender adjusts the MSS value for outgoing TCP traffic.

● set tcp-mss-receiver adjusts the MSS value for incoming TCP traffic.

This helps prevent issues with fragmentation and MTU mismatches, improving network performance and avoiding retransmissions.

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

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

● FortiGate retrieves and updates a predefined list of IPs and ports for different internet services from FortiGuard.

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

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

● ISDB works by matching traffic to known IP addresses and ports of categorized services.

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

The exhibit shows an active-passive HA (high availability) cluster with two virtual clusters, where FortiGate_A is the primary device for both Core1 and Core2. If the goal is to have FortiGate_B take over Core2 traffic, its priority must be higher than FortiGate_A for Virtual Cluster 2.

Currently, FortiGate_A has a priority of 150 for Core2, while FortiGate_B has 128. Increasing FortiGate_B’s priority to 200 ensures it becomes the primary for Virtual Cluster 2, taking over the Core2 VDOM traffic while keeping Core1 traffic on FortiGate_A.

Disabling override would prevent forced failovers but wouldn’t change the role distribution. Adjusting the load-balancing method is irrelevant in an active-passive setup, as it only applies to active-active configurations.

In ADVPN (Auto-Discovery VPN) configurations, security concerns include protecting peer IDs during VPN establishment. Peer IDs are exchanged in the IKE (Internet Key Exchange) negotiation phase, and their exposure could lead to privacy risks or targeted attacks.

● IKEv2 encrypts peer IDs, making it more secure compared to IKEv1, where peer IDs can be exposed in plaintext in aggressive mode.

● IKEv2 also provides better performance and flexibility while supporting dynamic tunnel establishment in ADVPN.

VXLAN (Virtual Extensible LAN) is an overlay network technology that extends Layer 2 networks over Layer 3 infrastructure. When VXLAN is used extensively on FortiGate, hardware acceleration is crucial for maintaining performance.

● NP7 (Network Processor 7) is Fortinet’s latest network processor designed to accelerate high-performance networking features, including:

● VXLAN encapsulation/decapsulation

● IPsec VPN offloading

● Firewall policy enforcement

● Advanced threat protection at wire speed

NP7 significantly reduces latency and improves throughput when handling VXLAN traffic, making it the best choice for large-scale VXLAN deployments.

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.

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.

From the exhibit, ISFW is part of a Security Fabric environment with NGFW-1 as the Fabric Root. In this architecture, FortiGate devices share security intelligence, including logs and detected threats.

ISFW is in a Security Fabric environment:

● Security Fabric allows devices like ISFW to receive threat intelligence from NGFW-1, even if UTM is not enabled locally.

● If NGFW-1 detects malware from IP 10.1.10.1 to 89.238.73.97, this information can be propagated to ISFW and FortiAnalyzer.

The firewall policy in NGFW-1 has UTM enabled:

● Even though ISFW does not have UTM enabled, NGFW-1 (which sits between ISFW and the external network) does have UTM enabled and is scanning traffic.

● Since NGFW-1 detects malware in the session, it logs the event, which is then sent to FortiAnalyzer.

In a transparent mode Virtual Domain (VDOM) configuration, FortiGate operates as a Layer 2 bridge rather than performing Layer 3 routing. The set forward-domain <domain_ID> command is used to control how traffic is forwarded between interfaces within the same transparent VDOM.

A forward-domain acts as a broadcast domain, meaning only interfaces with the same forward-domain ID can exchange traffic. This setting is commonly used to separate different VLANs or network segments within the transparent VDOM while still allowing FortiGate to apply security policies.