Fortinet NSE7_NST-7.2 - Fortinet NSE 7 - Network Security 7.2 Support Engineer

LDAP Authentication Process:

LDAP (Lightweight Directory Access Protocol) authentication involves several steps: Bind Request, Search Request, and Bind Response.

The Bind Request is used to authenticate the client to the LDAP server.

The Search Request is used to find the directory entry that matches the provided criteria.

Analyzing the Exhibit:

The exhibit shows a real-time LDAP debug output.

The debug log includes a successful resolution of the LDAP FQDN, indicating that the LDAP server was reached.

The debug log also shows the start of a search using the distinguished name (DN) base and a filter to locate the userjsmith.

Conclusion:

Since FortiOS successfully resolved the LDAP server and initiated a search for the userjsmith, it indicates that the LDAP server was located, and the search request was performed.

References:

Fortinet Community: Understanding LDAP authentication steps and troubleshooting​(Fortinet Docs)​.

Fortinet Documentation: LDAP integration and debugging in FortiOS​(Welcome to the Fortinet Community!)​.

IKE_SA_INIT:

This is the first exchange in IKEv2. It establishes a secure, authenticated channel between peers and negotiates cryptographic algorithms and keys.

IKE_Auth:

The second exchange authenticates the IKE SA (Security Association) using the previously negotiated keys and algorithms. This exchange also establishes the first IPsec SA.

Create_CHILD_SA:

This exchange creates additional IPsec SAs after the initial authentication. It can also be used to rekey existing IPsec SAs to maintain security.

Informational:

This is a generic exchange used for various purposes such as error notification, deletion of SAs, and other control messages.

References:

Fortinet Community: IKEv2 packet exchanges and troubleshooting

Fortinet Documentation: IPsec VPN Concepts

Session Table Overview:

The session table in FortiOS tracks all active and pending sessions. It includes details like the type of session (TCP, UDP, etc.), status, and statistics.

Interpreting the Exhibit:

The exhibit from thediagnose sys session statcommand shows detailed session statistics.

The specific value indicating "166 TCP sessions waiting to complete the three-way handshake" reflects the number of sessions that have initiatedbut not yet completed the TCP three-way handshake process (SYN, SYN-ACK, ACK).

References:

Fortinet Documentation: Understanding and troubleshooting session tables​(Hammertux)​.

Fortinet Community: Explanation of session states and statistics​(Welcome to the Fortinet Community!)​​(Hammertux)​.

Conserve Mode Activation:

FortiGate enters conserve mode to prevent system crashes when the memory usage reaches critical levels. The "red threshold" is the point at which FortiGate starts dropping new sessions to conserve memory.

When the system memory usage exceeds this threshold, the FortiGate will block new sessions that require significant memory resources, such as those needing content inspection.

Exiting Conserve Mode:

The "green threshold" is the memory usage level below which FortiGate exits conserve mode and resumes normal operation.

Once the system memory usage drops below this threshold, FortiGate will start allowing new sessions again.

References:

Fortinet Community: Understanding conserve mode and its thresholds​(Welcome to the Fortinet Community!)​​(Welcome to the Fortinet Community!)​.

Fortinet Documentation: Memory conserve mode and thresholds​(Welcome to the Fortinet Community!)​​(Fortinet GURU)​.

Automation Stitches Overview:

Automation stitches in FortiOS allow administrators to automate responses to specific events, such as running diagnostic commands or taking corrective actions when certain thresholds are exceeded.

Diagnostic Commands and Alerts:

Automation stitches can be configured to run diagnostic commands and attach the results to email alerts. This is useful for monitoring and troubleshooting purposes, particularly when CPU or memory usage exceeds set thresholds.

Sequential Execution with Parameters:

When actions are executed sequentially, each action can take parameters from the previous action as input. This enables more complex workflowsand automation sequences where the output of one action influences the next.

References:

Fortinet Documentation: Configuring and using automation stitches​(Welcome to the Fortinet Community!)​​(Hammertux)​.

Fortinet Community: Automation stitches and their applications in FortiOS​(Hammertux)​​(Fortinet GURU)​.

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)​.

The exhibit shows a sniffer capture where TCP port 8013 is being used for communication. The communication appears one-way, indicating potential issues with the upstream FortiGate receiving the necessary packets or being able to respond.

To ensure successful communication in a Security Fabric setup:

Ensure TCP port 8013 is not blocked along the way: Verify that no firewalls or network devices between the downstream and upstream FortiGates are blocking TCP port 8013. This port is crucial for Security Fabric communication.

Authorize the downstream FortiGate on the root FortiGate: In the Security Fabric, the root FortiGate must recognize and authorize the downstream FortiGate to allow proper communication and management.

Enable Security Fabric/Fortitelemetry on the receiving interface of the upstream FortiGate: The upstream FortiGate must have the Security Fabric or Fortitelemetry enabled on the interface that receives the communication from the downstream FortiGate. This enables proper data exchange and monitoring within the Security Fabric.

References

Fortinet Documentation on Security Fabric Configuration

Fortinet Community Discussion on Port Requirements

RTT (Round Trip Time):

RTT in the context of the FortiGuard server list indicates the time it takes for a request to be sent to a FortiGuard server and for a response to be received.

This metric helps determine the latency between the FortiGate device and the FortiGuard servers, which is crucial for ensuring efficient and quick updates and responses for services like web filtering and antivirus updates.

Server Selection:

The FortiGate device uses RTT values to prioritize servers. Servers with lower RTT values are preferred as they respond faster, ensuring minimal delay in processing requests.

This improves the overall performance of FortiGuard services by reducing the time it takes to communicate with the servers.

References:

Fortinet Community: Troubleshooting FortiGuard server connections and RTT values​(Welcome to the Fortinet Community!)​​(Fortinet Docs)​.

Fortinet Documentation: FortiGuard server settings and RTT explanation​(Welcome to the Fortinet Community!)​​(Fortinet Docs)​.

RADIUS Server IP Address:

The debug output shows that the RADIUS request was sent to the server atIP=172.25.188.164. This indicates that the RADIUS server being queried for authentication is indeed located at this IP address.

Authentication Result:

The debug output includes a line indicating the result for the RADIUS server:Result for radius svr 'RadiusServer' 172.25.188.164(0) is 0. A result code of0typically signifies that the authentication attempt was unsuccessful.

Authentication Scheme:

The debug output does not indicate that the authentication scheme used was pop3; it mentions using CHAP (Challenge Handshake Authentication Protocol).

Two-factor Authentication:

There is no indication in the debug output that two-factor authentication was required for this session.

References

Fortinet Network Security 7.2 Support Engineer Documentation

RADIUS Authentication Configuration and Debugging Guides