Fortinet FCSS_EFW_AD-7.6 - Fortinet NSE 7 - Enterprise Firewall 7.6 Administrator

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, like other security appliances, cannot analyze encrypted HTTPS traffic unless it decrypts it first. If only certificate inspection is enabled, FortiGate can see the certificate details (such as the domain and issuer) but cannot inspect the actual web content.

To fully analyze the traffic and detect potential malware threats:

● Full SSL inspection (Deep Packet Inspection) must be enabled in the SSL/SSH Inspection Profile.

● This allows FortiGate to decrypt the HTTPS traffic, inspect the content, and then re-encrypt it before forwarding it to the user.

● Without full SSL inspection, threats embedded in encrypted traffic may go undetected.

When designing an ADVPN (Auto-Discovery VPN) network for a large enterprise with spokes that have varying numbers of internet links, the main challenge is to minimize the number of peer connections and routes at the hub while maintaining scalability and efficiency.

Using a dynamic routing protocol (such as BGP or OSPF) with loopback interfaces helps in several ways:

● Reduces the number of peer connections at the hub by using a single loopback address per spoke instead of individual physical interfaces.

● Enables simplified route advertisement by dynamically learning and propagating routes instead of manually configuring static routes.

● Supports multiple internet links per spoke efficiently, as dynamic routing can automatically adjust to the best available path.

● Allows seamless failover if a spoke’s internet link fails, ensuring continuous connectivity.

When FortiGate is operating in proxy mode with full SSL inspection enabled, it inspects encrypted HTTPS traffic by default on port 443. However, some websites may use non-standard HTTPS ports (such as 8443), which FortiGate does not inspect unless explicitly configured.

To ensure that FortiGate inspects HTTPS traffic on port 8443, administrators must manually add port 8443 in the Protocol Port Mapping section of the SSL/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 of FortiGuard category-based web filtering.

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.

In this scenario, the corporate network and the new remote office network need to communicate over the Internet, which requires a secure and dynamic routing method. Since both networks are using OSPF (Open Shortest Path First) as the routing protocol, the best approach is to establish an OSPF over IPsec VPN to ensure secure and dynamic route propagation.

OSPF is already running on the corporate network, and extending it over an IPsec tunnel allows dynamic route exchange between the corporate FortiGate and the remote office FortiGate. IPsec provides encryption for traffic over the Internet, ensuring secure communication. OSPF over IPsec eliminates the need for manual static routes, allowing automatic route updates if networks change.

The new remote office's 192.168.1.0/24 subnet will be advertised dynamically to the corporate network without additional configuration.

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.

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.

From the BGP neighbor status output, the key issue is that BGP is stuck in the "Idle" state, meaning the FortiGate is unable to establish a BGP session with its peer 100.65.4.1 (Remote AS 65300).

The output also shows:

● "Not directly connected EBGP" → This means the BGP peer is not on the same subnet, requiring multihop BGP.

● "Update source is Loopback" → Since a loopback interface is used, FortiGate must be configured to allow BGP neighbors over multiple hops.

To resolve this issue, the administrator must enable ebgp-enforce-multihop, which allows BGP sessions to be established even when the neighbors are not directly connected.