FCSS_EFW_AD-7.6 Questions and Answers

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.

The best way to automate a firewall policy using a daily updated list of IP addresses is by using an external connector from Threat Feeds. This allows FortiGate to dynamically retrieve real-time threat intelligence from external sources and apply it directly to security policies.

By configuring Threat Feeds, the administrator can:

● Automatically update firewall policies with the latest malicious IPs daily.

● Block traffic from those IPs in real-time without manual intervention.

● Integrate with FortiGuard, third-party threat intelligence sources, or custom feeds (CSV, STIX/TAXII, etc.).

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.

When configuring a loopback interface as the BGP source for connecting to an ISP, two important settings must be applied:

1. Enable EBGP Multihop (ebgp-enforce-multihop)

BGP normally expects directly connected neighbors, but since the ISP and FortiGate A are using loopback interfaces, packets will not be sent directly between their physical interfaces.

The ebgp-enforce-multihop command allows BGP to form an eBGP peering over multiple hops.

2. Set the Update Source (update-source)

Since FortiGate is using a loopback interface as the source, the update-source command ensures that BGP updates originate from the loopback interface rather than a physical interface.

This is essential because BGP peers must match the source IP with the configured neighbor address.

Applying an aggressive IPS profile without prior testing can disrupt legitimate applications by incorrectly identifying normal traffic as malicious. To prevent disruptions while still monitoring for threats:

● Enable IPS in "Monitor Mode" first:

● This allows FortiGate to log and analyze potential threats without actively blocking traffic.

● Administrators can review logs and fine-tune IPS signatures to minimize false positives before switching to blocking mode.

● Verify and adjust signature patterns:

● Some signatures might trigger unnecessary blocks for legitimate application traffic.

● By analyzing logs, administrators can disable or modify specific rules causing false positives.

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 MAC address e0:23:ff:fc:00:86 follows the format used in FortiGate High Availability (HA) clusters. When FortiGate devices are in an HA configuration, they use virtual MAC addresses for failover and redundancy purposes.

The suspicious packet is related to a cluster that has VDOMs enabled:

FortiGate devices with Virtual Domains (VDOMs) enabled use specific MAC address ranges to differentiate HA-related traffic. This MAC address is likely part of that mechanism.

The suspicious packet is related to a cluster with a group-id value lower than 255:

FortiGate HA clusters assign virtual MAC addresses based on the group ID. The last octet (00:86) corresponds to a group ID that is below 255, confirming this option.

The OSPF database optimization is necessary to reduce unnecessary routing information and improve network performance. In the given topology, Area 0.0.0.1 is a non-backbone area connected to Area 0.0.0.0 (the backbone area) through an Area Border Router (ABR).

To optimize OSPF in this scenario, configuring Area 0.0.0.1 as a Stub Area will:

● Reduce the size of the OSPF database by preventing external routes (from outside OSPF) from being injected into Area 0.0.0.1.

● Allow only intra-area and inter-area routes, meaning routers in Area 0.0.0.1 will rely on a default route for external destinations.

● Improve convergence time and reduce router processing load since fewer LSAs (Link-State Advertisements) are exchanged.

The diagram shows a FortiGate connected to two FortiSwitches, which suggests the use of FortiLink, Fortinet's protocol for managing switches directly from a FortiGate. Since multiple connections are being used, the LAN interface must be set to 802.3ad (LAG) mode to aggregate the links for redundancy and load balancing.

This setup allows FortiGate to handle VLAN assignments dynamically, as seen with VLAN 10 (192.168.15.1/24). FortiLink ensures seamless integration between FortiGate and FortiSwitches, making STP unnecessary because Fortinet's MCLAG prevents 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.

The best way to block outdated SSL/TLS versions is to configure the SSL/SSH inspection profile to enforce a minimum SSL/TLS version and disable weak SSL versions.

By setting the minimum allowed SSL version in the HTTPS settings of the SSL/SSH inspection profile, FortiGate will:

● Block any connection using outdated SSL/TLS versions (such as SSLv3, TLS 1.0, or TLS 1.1).

● Enforce secure communication using only strong SSL/TLS versions (such as TLS 1.2 or TLS 1.3).

● Protect users from man-in-the-middle (MITM) and downgrade attacks that exploit weak encryption.

neighbor-group:

● This command is used to group multiple BGP neighbors with the same configuration, reducing redundant configuration.

● Instead of defining individual BGP settings for each spoke, the administrator can create a neighbor-group and apply the same policies, reducing manual work.

neighbor-range:

● This command allows the configuration of a range of neighbor IPs dynamically, reducing the need to manually define each spoke neighbor.

● It automatically adds BGP neighbors that match a given prefix, simplifying deployment.

In a hub-and-spoke topology using OSPF over IPsec VPNs, the point-to-multipoint network type is necessary to establish neighbor adjacencies between the hub and spokes. This network type ensures that OSPF operates correctly without requiring a designated router (DR) and allows dynamic routing updates across the IPsec tunnels.