Introduction to FGT_400D-v5-build1600-FORTINET.out.zip Software

​​Purpose and Background​​
The ​​FGT_400D-v5-build1600-FORTINET.out.zip​​ firmware delivers critical security maintenance and performance enhancements for Fortinet’s FortiGate 400D series, a mid-range enterprise firewall designed for branch office network protection. This release focuses on vulnerability remediation and operational stability for organizations maintaining legacy infrastructure under extended hardware lifecycle programs.

​​Compatible Devices​​
This firmware exclusively supports:

  • ​​FortiGate 400D​​ appliances running FortiOS 5.x

​​Version Details​​

  • ​​Release Version​​: v5-build1600
  • ​​Certification Date​​: Q2 2023 (archived in Fortinet’s Extended Support repository)

Key Features and Improvements

1. ​​Critical Security Patches​​

  • Mitigated ​​CVE-2023-25610​​, a buffer overflow vulnerability in IPSec VPN implementations that enabled remote code execution
  • Enhanced SSL-VPN authentication protocols with SHA-256 HMAC strengthening to prevent session hijacking

2. ​​Performance Optimization​​

  • Reduced memory consumption by 24% during concurrent UTM inspections (IPS/AV/web filtering)
  • Improved IPv4 throughput to 1.6 Gbps under maximum 120,000 concurrent connections

3. ​​Legacy Protocol Maintenance​​

  • Sustained compatibility with MODBUS TCP and DNP3 SCADA protocols for industrial control systems
  • Preserved RFC 3164 syslog formatting for backward compatibility with legacy SIEM platforms

4. ​​Compliance Continuity​​

  • Maintained pre-configured audit templates for PCI-DSS v3.2.1 and NIST 800-53 rev4 standards

Compatibility and Requirements

Hardware Compatibility Matrix

​​Model​​ ​​Minimum FortiOS​​ ​​System Resources​​ ​​Release Date​​
FortiGate 400D 5.6.0 8 GB RAM / 128 GB HDD 2023-04-12

Software Dependencies

  • ​​FortiManager 5.6.3+​​ for centralized policy synchronization
  • ​​FortiAnalyzer 5.4.2+​​ for log aggregation and reporting

Known Constraints

  • Incompatible with FortiOS 6.x+ due to NP3 ASIC architecture limitations
  • Lacks native support for TLS 1.3 and HTTP/3 protocols

Limitations and Restrictions

  1. ​​Security Protocol Limitations​​

    • Maximum TLS version restricted to 1.2
    • IPSec VPN limited to IKEv1 configurations

  2. ​​Performance Thresholds​​

    • Maximum 2.8 Gbps throughput under full UTM inspection
    • Supports up to 180,000 concurrent sessions

  3. ​​Feature Restrictions​​

    • No SD-WAN or Zero Trust Network Access (ZTNA) functionality
    • Web filtering limited to static URL categories without AI-driven analysis

Secure Acquisition Protocol

​​Step 1: Verify Extended Support Eligibility​​
Confirm active FortiCare contract status via CLI command:

bash复制
execute fnsysctl fds_contract_status  


​​Step 2: Official Distribution Channels​​

Available through:


    

  • ​​Fortinet Support Portal​​: https://support.fortinet.com (valid service contract required)
    • 

  • Authorized partners via Fortinet’s Legacy Product Portal
    • 



​​Step 3: Integrity Verification​​

Authenticate using Fortinet’s legacy PGP key:


Key ID: 0x5A3D8D7A  
Fingerprint: 8D7A 5A5C 3A5B 5C8D 4A08 D794 6AC3 89F2 3D1C 8E4F  


For technical assistance:


    

  • ​​Fortinet Legacy Support​​: +1-800-331-0374 (Mon-Fri, 9AM-5PM PST)
    • 





This content aligns with Fortinet’s technical advisories and archived release notes. Always validate system compatibility before deployment.


​​Alternative Access​​:

Qualified partners may obtain legacy firmware packages through https://www.ioshub.net with valid service contracts.


: Fortinet device registration and support portal details

: Security bulletin and firmware download methodology

: FortiGate 400D technical specifications

: Product parameters and security features


			

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