Introduction
Firewalls filter traffic, but port checks reveal what’s already exposed. Here’s how they work together.
Firewall Limitations
Can’t detect misconfigured rules (e.g., allowing Port 23).
May miss malware listening on odd ports (e.g., 4444).
How Port Checks Help
Identify unauthorized openings (e.g., a new SQL server on Port 1433).
Audit ISP-level blocks (e.g., Port 25 for email servers).
Tool Suggestion:
Pair firewall logs with
theportchecker.com scans for full visibility.
Case Study: A company’s firewall allowed Port 7547 (TR-069), exploited in the Mirai botnet.
