The Role of Firewall Technology in Securing the Perimeter
The Security Gatekeeper
A firewall is the barrier between your trusted internal network and the untrusted external internet. It analyzes incoming and outgoing network traffic based on a defined set of rules to determine whether to allow or block specific data packets.
Types and Functions
- **Packet-Filtering Firewall:** The simplest type, checking only the source and destination IP addresses and ports. While fast, it offers limited security.
- **Stateful Inspection Firewall:** Tracks the state of active connections, only allowing traffic that belongs to an established session. This provides much stronger security than basic packet filtering.
- **Next-Generation Firewall (NGFW):** The modern standard for businesses. NGFWs incorporate advanced features beyond basic packet filtering, including Intrusion Prevention Systems (IPS), deep packet inspection, application control, and built-in antivirus/malware scanning.
**Key Best Practice:** Ensure all default “allow-all” rules are disabled. Firewalls should operate on the principle of **”Deny All, Except What is Explicitly Permitted”** (the principle of least privilege) to minimize the attack surface.