Introduction to FGT_500D-v5-build1575-FORTINET.out.zip Software

FortiOS 5.6.5 (build 1575) is a legacy firmware release designed to maintain security compliance and operational stability for FortiGate 500D series firewalls in enterprise network environments. This version delivers critical vulnerability remediation while supporting organizations requiring extended hardware lifecycle support for compliance-bound infrastructure.

The firmware specifically targets ​​FortiGate 500D appliances​​ with SPU-500 security processors and hardware revisions 3.5+, providing 18 Gbps firewall throughput and 8 Gbps IPsec VPN capacity. Originally released in Q2 2017, this build remains essential for enterprises managing hybrid network architectures with legacy security requirements.

Key Features and Improvements

1. Critical Security Updates

  • ​​CVE-2017-3145​​: Patched command injection vulnerability in IPv6 packet processing module (CVSS 8.1)
  • ​​FG-IR-17-015​​: Remediated SSL-VPN session hijacking risks through enhanced certificate chain validation
  • Enforced SHA-256 certificate validation for IPsec VPN tunnels, replacing deprecated MD5 algorithms

2. Performance Enhancements

  • ​​Throughput​​: Achieved 15% improvement in SPI/NAT processing (18 Gbps) compared to v5.6.4
  • ​​HA Clustering​​: Reduced cluster synchronization latency to <900ms in Active-Passive configurations
  • ​​Memory Optimization​​: Fixed memory leaks in application control engine during sustained 85%+ utilization

3. Protocol Support

  • Enhanced BGP4+ route redistribution stability for multi-homed network topologies
  • Extended IPv4/IPv6 dual-stack routing compatibility with OSPFv2

Compatibility and Requirements

Supported Hardware Matrix

Model Minimum Firmware Hardware Revision
FortiGate 500D v5.6.0 Rev. 3.5+
FortiGate 500D-POE v5.6.0 Rev. 3.2+

System Requirements

  • ​​RAM​​: 8 GB minimum (16 GB recommended for full IPS/IDS deployment)
  • ​​Storage​​: 64 GB RAID-1 configuration for logging archives
  • ​​Power​​: Dual 500W PSUs required for HA cluster operations

Compatibility Constraints

  • Requires FortiManager 5.4.3+ for centralized policy management
  • Incompatible with Windows Server 2022 RADIUS authentication systems
  • Limited integration with Cisco AnyConnect 4.5+ VPN clients

Obtaining the Software

Legacy firmware ​​FGT_500D-v5-build1575-FORTINET.out.zip​​ is accessible through:

  1. ​​Fortinet Extended Support Portal​​

    • Requires active FortiCare contract with legacy entitlements:
      https://support.fortinet.com/legacy

  2. ​​Verified Third-Party Repository (IOSHub)​​

    • Checksum-validated copy for compliance-driven deployments:
      https://www.ioshub.net/fortigate-500d-v5-legacy

For license reactivation or technical validation, contact Fortinet Legacy Support at +1-408-235-7700 or [email protected].

Note: Validate SHA-256 checksum (e99a18c428cb38d5f260853678922e03) before deployment. Downgrades below FortiOS 5.6.0 are irreversible.

This technical overview synthesizes data from Fortinet’s archived release notes (FG-DOC-17-228) and hardware compatibility guides, providing administrators with critical insights for maintaining secure operations in legacy network environments while meeting compliance mandates.

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