This means a is already occupied.
Windows 11 enables IPv6 by default. Many services bind to [::] (IPv6 wildcard), which on Windows via IPv4-mapped addresses ( ::ffff:192.168.1.1 ). Thus, seeing only [::]:445 does not mean IPv4 is blocked — it’s dual-stack.
This displays:
: For a more detailed, real-time view, Microsoft recommends the TCPView utility from Sysinternals, which provides a comprehensive GUI for monitoring connections. How to Open a Port (Firewall Exception)
To open a TCP port from Command Prompt:
The IP address and corresponding port number (e.g., 127.0.0.1:443 ) currently in use.
Windows 11 categorizes connections into three distinct network profiles: windows 11 open ports
netstat -ano | findstr :PORT_NUMBER
Windows has a kernel-mode HTTP listener ( HTTP.sys ) that allows multiple applications to share ports like 80 and 443 via URL reservations. View HTTP.sys listeners: This means a is already occupied
Reserved for core system services and ubiquitous internet protocols (e.g., Port 80 for HTTP, Port 443 for HTTPS, and Port 22 for SSH).
Open ports are necessary for various reasons: Thus, seeing only [::]:445 does not mean IPv4