OT Cybersecurity Best Practices for SMBs: Transferring Files to an OT Environment

## Executive Summary This guidance describes an ideal secure file-transfer architecture for environments with corporate, DMZ, and OT/ICS trust zones, recommending at least three dedicated file-transfer servers, layered firewalls, IDS/IPS, anti-malware (A/V and selective EDR), comprehensive logging/monitoring, and strict authentication controls (VPN with MFA, domain separation, and no dual-homed assets) to prevent cross-zone compromise and ensure authorized, auditable transfers.