This guide walks through setting up a Linux firewall with multiple network interfaces, configuring a web server in a DMZ zone, restricting ICMP, and changing SSH ports to securely enable internal and external access while preventing unwanted ping traffic.
This guide explains how firewalls protect networks by using stateful filtering, deep packet inspection of application-layer data, and security zones such as inside, outside, and DMZ, illustrating configuration examples, ACL usage, and best‑practice traffic control.
This article explains why remote access to industrial control systems is essential, outlines the risks demonstrated by high‑profile attacks, and provides detailed best‑practice guidance—including DMZ architecture, authentication, jump hosts, file transfer, and policies for direct connections—to securely manage OT environments.
A DMZ (Demilitarized Zone) acts as a buffer between internal and external networks, allowing public services like web, email, and FTP while shielding internal systems from attacks, and its security policies define how traffic flows among internal, DMZ, and external zones.
The article explains how a senior architect leverages SSH reverse tunneling and remote port forwarding to enable a headquarters server to reach a branch office's internal web server despite restrictive network policies, detailing the commands, verification steps, and packet flow involved.
This article explains why remote access to industrial control systems is essential, outlines the Purdue Enterprise Reference Architecture levels, and provides detailed best‑practice recommendations—including DMZ design, authentication, jump‑host usage, secure file transfer, and controls for direct connections—to mitigate the significant security risks associated with remote ICS access.
