Windows provides a variety of built-in commands and utilities for system administration, network diagnostics, and file management. Below is a curated list of common used tools with brief explanations and practical examples.

• rd – Removes empty directories.
• cd – Changes the current directory.
• dir – Lists contents of the current directory.
• mstsc – Launches Remote Desktop Connection.
• ipconfig – Displays IP configuration details.
• telnet <IP> <port> – Tests connectivity to a specific port on a remote host.
• netstat -aon – Shows all active connections and listening ports along with associated process IDs (PIDs).

To identiyf which application is using port 8002:

netstat -aon | findstr :8002

Sample output:

TCP    127.0.0.1:8001    127.0.0.1:8002    ESTABLISHED    8092
TCP    127.0.0.1:8002    127.0.0.1:8001    ESTABLISHED    8092

The PID 8092 corresponds to the process using the port. To determine the executable name:

tasklist /FI "PID eq 8092"

Output:

Image Name      PID   Session Name     Session#   Mem Usage
nessusd.exe     8092  Services         0          35,152 K

Terimnate the process if needed (requires elevated privileges):

taskkill /PID 8092 /F

Other useful utilities include:

• gpedit.msc – Opens Local Group Policy Editor.
• sndrec32 – Legacy Sound Recorder (deprecated in newer Windows versions).
• nslookup – Queries DNS to resolve domain names to IP addresses.
• explorer – Launches File Explorer.
• logoff – Logs off the current user.
• shutdown /s /t 60 – Shuts down the system after a 60-second delay.
• lusrmgr.msc – Manages local users and groups.
• services.msc – Configures Windows services.
• notepad – Opens Notepad.
• cleanmgr – Starts Disk Cleanup.
• compmgmt.msc – Opens Computer Management console.
• calc – Launches Calculator.
• chkdsk – Checks disk integrity and repairs file system errors.
• devmgmt.msc – Opens Device Manager.
• regsvr32 /u *.dll – Unregisters DLL files (use with caution).
• dxdiag – Displays DirectX diagnostic information.
• msconfig – Opens System Configuration utility.
• perfmon.msc – Launches Performance Monitor.
• winver – Shows Windows version information.
• sfc /scannow – Scans and restores protected system files.
• taskmgr – Opens Task Manager.
• regedit – Launches Registry Editor.
• wmimgmt.msc – Opens WMI Control.
• osk – Starts On-Screen Keyboard.
• odbcad32 – Configures ODBC data sources.
• tracert <hostname> – Traces the route packets take to reach a destination.
• certmgr.msc – Manages security certificates.
• secpol.msc – Opens Local Security Policy editor.
• syskey – Configures system encryption options (primarily for legacy Windows XP).