Port Scanner Articles

IPv6's Address Space Is Too Big to Scan — Here's Why That Doesn't Make It Secure

A misconfigured open port on an IPv4 server gets found by automated scanners within hours, because the entire IPv4 address space is small enough to scan exhaustively. The same misconfiguration on an IPv6 server might never be found this way — not because it's more secure, but because 2^128 addresses is too large to scan at any practical rate. Here's how IPv6 hosts actually get discovered instead (DNS records, certificate transparency logs, predictable address patterns), and why "too big to scan" is security through obscurity, not security.

Jun 15, 2026

NAT and Port Forwarding for Home Networks: Why "Filtered" Doesn't Mean "Firewalled"

Most home network ports show "filtered" from the internet — not because of a configured firewall, but as a side effect of how NAT works: incoming connections without an existing mapping have nowhere to go. Here's the open/closed/filtered distinction, how NAT creates this effect, why port forwarding and UPnP change it, and the CGNAT limitation that can make port forwarding fail entirely.

Jun 12, 2026

Cloud Security Groups: AWS, GCP, Azure — Common Misconfigurations and How to Audit Them

Every major cloud breach has the same pattern: legitimate infrastructure, misconfigured security groups. Here's how AWS Security Groups, GCP Firewall Rules, and Azure NSGs work, the most common dangerous misconfigurations (databases open to 0.0.0.0/0), and why scanning your own cloud infrastructure is security hygiene.

Jun 10, 2026

Common Server Ports: Which Should Be Open and Which Must Be Firewalled

Every open port is a potential attack surface. Here's a practical reference of common ports — what they do, which should be publicly accessible, and which are commonly left dangerously exposed — with guidance on interpreting scan results.

Jun 9, 2026

Port Scanner — Check Open Ports & Verify Server Security Configuration

Learn how port scanning works, what common port numbers mean, how to identify dangerous open ports, and how to use a free port scanner to verify your server's security posture.

Jun 6, 2026