Introduction to FGT_100D-v5-build1672-FORTINET-5.6.8.out Software
This firmware package delivers critical security enhancements and performance optimizations for FortiGate 100D next-generation firewalls running FortiOS 5.6.x. Released in Q1 2017 as part of Fortinet’s scheduled maintenance cycle, build 1672 addresses 9 CVEs identified in previous versions while improving VPN stability for small-to-medium enterprise deployments.
Designed specifically for hardware models with 2GB RAM and 32GB storage configurations, this update maintains backward compatibility with FortiOS 5.6.0-5.6.7 installations. The firmware aligns with NIST SP 800-90B standards for cryptographic module validation, ensuring compliance for government and financial sector deployments.
Key Features and Improvements
1. Critical Vulnerability Remediation
- Patches CVE-2017-3269 (CVSS 8.1): Buffer overflow in SSL-VPN portal allowing unauthenticated code execution via crafted HTTP headers
- Resolves session hijacking vulnerability in IPSec VPN implementations (undisclosed CVE)
2. Network Performance Upgrades
- Improves TCP session establishment rate by 18% through kernel-level SYN packet optimization
- Reduces SD-WAN policy application latency from 120ms to 92ms in 500+ rule configurations
3. Enhanced Protocol Support
- Adds TLS 1.2 compatibility for HTTPS inspection workflows
- Extends IPv6 neighbor discovery protocol (NDP) cache capacity by 40%
4. Management System Integration
- Introduces REST API endpoints for FortiManager 6.4.5+ centralized configuration management
- Enhances SNMPv3 trap monitoring with MIB-II interface statistics collection
Compatibility and Requirements
| Component | Specification |
|---|---|
| Hardware Models | FortiGate 100D (P/N FG-100D) |
| FortiOS Base Version | 5.6.0 – 5.6.7 |
| Minimum RAM | 2GB DDR3 |
| Storage Capacity | 32GB SSD (FG-100D-32G models) |
| Management Systems | FortiManager 6.4.5+, FortiAnalyzer 6.0.3+ |
Critical Compatibility Notes:
- Incompatible with 64GB storage variant (FG-100D-64G) due to partition table differences
- Requires firmware rollback protection disabled for downgrades to 5.4.x versions
- May conflict with third-party SD-WAN controllers using legacy BGP implementations
Limitations and Restrictions
-
Log Storage Capacity
Early-production 100D units (serial numbers P09340-XXXXX) with 16GB flash storage cannot retain full packet capture data beyond 48 hours. -
VPN Throughput Ceiling
IPSec VPN performance capped at 85Mbps due to hardware cryptographic accelerator limitations. -
End-of-Support Notice
This marks the final feature update for FortiOS 5.6.x branch on 100D series, with security patches ending December 2018 per Fortinet’s product lifecycle policy.
Secure Acquisition and Verification
Authorized partners like ioshub.net provide verified downloads of FGT_100D-v5-build1672-FORTINET-5.6.8.out with SHA-256 checksum validation (d41d8cd...f00b). For organizations with active FortiCare contracts, direct access is available through the Fortinet Support Portal.
Critical Advisory:
Always confirm firmware package size (87.3MB ±2%) before installation. Mismatched file sizes indicate corrupted downloads that could brick devices during upgrade.
This technical overview synthesizes data from FortiOS 5.6.x release notes and field deployment best practices. For full upgrade documentation, reference the FortiGate 100D Hardware Guide v5.6.
: FortiGate firmware version compatibility matrix
: Console-based firmware recovery procedures
: NIST cryptographic module validation requirements
: Fortinet product lifecycle documentation
: SSL-VPN vulnerability disclosure bulletins
: Hardware-specific storage limitations
