Free Practice Questions for Fortinet FCSS_EFW_AD-7.6 Exam

The issue occurs because FortiGate enforces the "do not fragment" (DF) bit in the packet, and the packet size exceeds the MTU of the network path. When the Windows PC1 (with an MTU of 1500 bytes) attempts to send a 1400-byte packet, the FortiGate interface (with an MTU of 1000 bytes) needs to fragment it. However, since the DF bit is set, FortiGate drops the packet instead of fragmenting it.

To resolve this, the user should adjust the ping packet size to fit within the path MTU. In this case, reducing the packet size to 972 bytes (1000 bytes MTU minus 28 bytes for the IP and ICMP headers) should allow successful transmission.

The Fortinet FGSP (FortiGate Session Life Support Protocol) cluster allows session synchronization between two FortiGate devices to provide seamless failover. However, ICMP (ping) is a connectionless protocol, and by default, FortiGate does not synchronize connectionless sessions unless explicitly enabled.

In the exhibit:

● The command get system session list | grep icmp on FortiGate_B returns no output, meaning that ICMP sessions are not being synchronized from FortiGate_A.

● If session-pickup-connectionless is disabled, FortiGate_B will not receive ICMP sessions, causing packet loss during failover.

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

● The neighbor-group parameter is used to apply pre-defined settings (such as AS number) to dynamically discovered BGP neighbors.

● The advpn neighbor-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 allows dynamic BGP peer discovery by defining a range of potential neighbor IPs (172.16.1.1 - 172.16.1.255).

● Since each spoke has a unique /32 IP within this subnet, this ensures that any spoke within the 172.16.1.0/24 range can automatically establish a BGP session with the hub.

Comprehensive and Detailed 150 to 200 words of Explanation From Exact Extract of Enterprise Firewall 7.6 Administrator documents:

Based on the FortiOS 7.6 Administration Guide and the Life of a Packet documentation (Parallel Path Processing), the FortiGate follows a specific, hardcoded sequence when processing the first packet of a new session. This process is divided into several stages: Ingress, Kernel, and Egress.

The very first stage is Ingress, where all packets accepted by a network interface are processed by the TCP/IP stack. Immediately following this, the packet must pass through IP integrity header checking. This step involves reading the packet headers to verify that the packet is a valid protocol (TCP, UDP, ICMP, etc.) and that the header length is correct. This sanity check is performed before any other security functions, such as decryption (which occurs later in the Ingress stage) or the Reverse Path Forwarding (RPF) check (which occurs even later during the Routing step in the Kernel stage).

Installation of the session key (Option A) only occurs after the packet has matched a firewall policy and the session has been fully established and offloaded to the NPU. Therefore, IP integrity header checking is the absolute first security-related validation performed on an incoming packet.

When using IPsec VPNs and VXLAN, additional headers are added to packets, which can exceed the default 1500-byte MTU. This can lead to fragmentation issues, dropped packets, or degraded performance.

To resolve this, the MTU (Maximum Transmission Unit) should be adjusted only if all devices in the network path support it. Otherwise, some devices may still drop or fragment packets, leading to continued issues.

Why adjusting MTU helps:

● VXLAN adds a 50-byte overhead to packets.

● IPsec adds additional encapsulation (ESP, GRE, etc.), increasing the packet size.

● If packets exceed the MTU, they may be fragmented or dropped, causing intermittent connectivity issues.

● Lowering the MTU on interfaces ensures packets stay within the supported size limit across all network devices.

When adding an additional FortiGate to an enterprise network that is already reaching its resource limits, the goal is to distribute traffic efficiently and ensure high availability.

FGSP (FortiGate Session Life Support Protocol) with external load balancers

FGSP allows session-aware load balancing between multiple FortiGate units without requiring them to be in an HA (High Availability) cluster.

With external load balancers, incoming traffic is evenly distributed across multiple FortiGate devices.

This approach is useful for scaling out traffic handling capacity while ensuring that sessions remain synchronized between firewalls.

FGSP is effective when stateful failover is required but without the constraints of traditional HA.

FGCP (FortiGate Clustering Protocol) in active-active mode and with switches

FGCP active-active mode enables multiple FortiGate devices to share traffic loads, increasing throughput and efficiency.

Active-active mode is suitable for balancing UTM processing across multiple FortiGates, making it ideal when resource limits are a concern.

Using switches ensures redundancy and avoids single points of failure in the network.

This mode is commonly used in enterprise networks where both scalability and redundancy are required.

IKEv2 (Internet Key Exchange version 2) is an improvement over IKEv1, offering enhanced security, efficiency, and flexibility in VPN configurations.

It includes stronger Diffie-Hellman (DH) groups, such as Elliptic Curve (ECP) groups.

IKEv2 supports stronger cryptographic algorithms, including Elliptic Curve Diffie-Hellman (ECDH) groups such as ECP256 and ECP384, providing improved security compared to IKEv1.

It supports the extensible authentication protocol (EAP).

IKEv2 natively supports EAP authentication, which allows integration with external authentication mechanisms such as RADIUS, certificates, and smart cards. This is particularly useful for remote access VPNs where user authentication must be flexible and secure.

FortiGate devices with NP6 (Network Processor 6) acceleration offload traffic directly to hardware, bypassing the CPU for improved performance. When auto-asic-offload is enabled in a firewall policy, most of the traffic does not reach the CPU, which means it won't be captured by the standard sniffer trace command.

Since NP6-accelerated traffic is handled entirely in hardware, only a small portion of initial packets (such as session setup packets or exceptions) might be seen in the sniffer output. To capture all packets, the administrator must disable hardware offloading using:

config firewall policy

edit

set auto-asic-offload disable

end

Disabling ASIC offload forces traffic to be processed by the CPU, allowing the sniffer tool to capture all packets.

The FortiGate SSL/SSH inspection profile is configured for Full SSL Inspection, which is necessary to analyze encrypted HTTPS traffic. However, the firewall policy is protecting an SSL server (the Linux server hosting the website), and currently, the SSL/SSH profile only applies to client-side SSL inspection.

To detect HTTPS-based attacks targeting the Linux server:

● FortiGate must act as an SSL intermediary to inspect encrypted traffic destined for the web server.

● The administrator must upload the SSL certificate of the Linux web server to FortiGate so that the server-side SSL inspection can decrypt incoming HTTPS traffic before analyzing it.