NSE7_NST-7.2 Sample Questions Answers

Routing Table Analysis:

The first command output (get router info routing-table database) shows two default routes:

One viaport1with a distance of10.

One viaport2with a distance of20.

The second command output (get router info routing-table all) only shows the route viaport1.

Administrative Distance:

The administrative distance (AD) is a measure used by routers to select the best path when there are multiple routes to the same destination. The lower the distance, the more preferred the route.

In this scenario, the route viaport1has a lower distance (10) compared to the route viaport2(20), making it the preferred route.

Route Selection:

Since the route viaport1has a lower distance, it is the only one installed in the active routing table, which is why it appears in the second command output, and theport2route does not.

References:

Fortinet Community: Routing behavior depending on distance and priority​(Welcome to the Fortinet Community!)​​(Welcome to the Fortinet Community!)​.

Fortinet GURU: Route priority and administrative distance explanations​(Fortinet GURU)​.

Statistics and Configuration Information:

Application-layer test commands can display detailed statistics and configuration information about specific features or processes. For example, commands likediagnose vpn ipsec tunnel listprovide detailed statistics about VPN tunnels.

Real-time Debugs:

These commands also facilitate real-time debugging of applications and processes. For instance, usingdiagnose debug applicationfollowed by the specific application, such asfssod, provides real-time debug information which is crucial for troubleshooting.

References:

Fortinet Community: Useful FSSO Commands and Troubleshooting​(Welcome to the Fortinet Community!)​​(Welcome to the Fortinet Community!)​.

Fortinet Documentation: Application-layer Test Commands​(Fortinet GURU)​.

SNI and Certificate Mismatch:When the Server Name Indication (SNI) does not match either the Common Name (CN) or any of the Subject Alternative Names (SAN) in the server certificate, FortiGate's default behavior is to consider this as an invalid SSL/TLS configuration.

Default Action:FortiGate, under default settings for SSL certificate inspection, will close the connection to prevent potential security risks associated with mismatched certificates.

References:

Fortinet Community: SSL Certificate Inspection Configuration and Behavior​(Welcome to the Fortinet Community!)​.

Soft Reset of BGP:

Performing a soft reset of BGP is a common method to resolve issues where prefixes are not being received. It forces both BGP peers to resend their complete routing tables to each other.

This can be done using the command:execute router clear bgp soft inandexecute router clear bgp soft out.

Network Import Check:

Thenetwork-import-checkcommand controls whether the FortiGate should verify that the prefix exists in the routing table before advertising it.

Disabling this check can resolve issues where valid prefixes are not advertised due to stringent verification.

The command to disable this is:config router bgp set network-import-check disable end.

BGP Configuration Verification:

Ensure that the BGP configuration on FGT-B is correctly set to advertise the network 172.16.54.0/24.

Verify that the network statement is correctly configured and matches the intended prefix.

References:

Fortinet Community: Technical Note on Configuring BGP​(Welcome to the Fortinet Community!)​.

Fortinet Documentation: Configuring BGP on FortiGate​(Fortinet Document Library)​.

IKE (Internet Key Exchange):IKE is a protocol used to set up a security association (SA) in the IPsec protocol suite. It is utilized to negotiate, create, and manage SAs.

NAT-T (Network Address Translation-Traversal):NAT-T is used to enable IPsec VPN traffic to pass through NAT devices. It encapsulates IPsec ESP packets into UDP packets.

Transport Protocol:Both IKE and IKE NAT-T use UDP as their transport protocol.

Port Numbers:By default, IKE uses UDP port 500. NAT-T typically uses UDP port 4500. However, these port numbers can be configured as needed.

References:

Fortinet Network Security Support Engineer Study Guide for FortiOS 7.2​(Fortinet Docs)​​(ebin.pub)​.

Fortinet Documentation on IPsec VPN Configuration​(Fortinet Docs)​.

Refused Connection:A refused connection typically indicates a mismatch in the TCP port configuration between the FortiGate and the collector agent. Ensuring both are configured to use the same TCP port is crucial for proper connectivity.

Mismatched Pre-Shared Password:If the pre-shared password configured on the FortiGate does not match the one set on the collector agent, authentication will fail, leading to connectivity issues.

Inability to Reach IP Address:This can occur due to network issues such as incorrect routing, firewall rules blocking traffic, or the collector agent being down. Verifying network connectivity and the status of the collector agent is necessary to resolve this issue.

References:

Fortinet Community: Troubleshooting FSSO Connectivity Issues​(Welcome to the Fortinet Community!)​​(Welcome to the Fortinet Community!)​​(Welcome to the Fortinet Community!)​.

Diagnose NPU NP6 Port-list Disable Command:

Thediagnose npu np6 port-list disablecommand disables specific ports on the NP6 processor. This can help in cases where you need to analyze traffic and the hardware offloading is interfering.

Command:diagnose npu np6 port-list disable 5 17(as shown in Option A).

Diagnose NPU NP6 Fastpath Disable Command:

Disabling the fastpath feature on NP6 can also allow for better visibility into the traffic as it bypasses hardware acceleration, which might obscure traffic details.

Command:diagnose npu np6 fastpath disable 0(as shown in Option C).

References:

Fortinet Documentation on Troubleshooting BGP and NPU Settings​(Fortinet Docs)​.

Fortinet Community Technical Notes on NPU and Traffic Analysis​(Welcome to the Fortinet Community!)​.

Understanding OSPF Roles:

In OSPF (Open Shortest Path First), routers can have different roles: Designated Router (DR), Backup Designated Router (BDR), and DROther. These roles help manage and optimize the OSPF network traffic.

DR and BDR are elected to minimize the number of adjacencies and reduce the amount of routing information exchange.

DROther routers are neither DR nor BDR but can still participate in the OSPF network by maintaining adjacencies with DR and BDR.

Analyzing the Exhibit:

The exhibit shows the OSPF neighbor states for the local FortiGate.

Neighbor ID 0.0.0.1 is in the state Full/DR (Designated Router).

Neighbor ID 0.0.0.3 is in the state Full/DROther (DROther).

Neighbor ID 0.0.0.10 has no specific designation, implying it is neither DR nor BDR.

Conclusion:

Since the local FortiGate shows neighbors in Full/DR and Full/DROther states and itself does not have a state of DROther, it can be concluded that the local FortiGate is not a DROther.

References:

Fortinet Community: Understanding OSPF roles and states​(Welcome to the Fortinet Community!)​​(cyruslab)​.

Fortinet Documentation: OSPF neighbor states and elections​(Fortinet Docs)​.

Session Synchronization:

FortiGate HA (High Availability) ensures that active sessions are synchronized between the primary and secondary devices. This synchronization allows for seamless failover and continuity of sessions.

Handling NAT Sessions:

The session in the exhibit has NAT applied, as indicated by thehook=post dir=org act=snatentry. FortiGate's HA setup is designed to handle such sessions, ensuring that traffic continues without interruption during failover.

Session Preservation:

Even with the presence of NAT, the session state is preserved across the HA devices. This means that ongoing sessions do not require re-establishment by the client, thus providing a seamless experience.

References:

Fortinet Documentation: HA session synchronization and failover

Fortinet Community: Understanding session synchronization in FortiGate HA