Common Commands For IT Support

Here are some common command prompts and their usage on Windows that are essential for IT support jobs. These commands can help with system diagnostics, network management, and general troubleshooting:

Network Configuration

• Command: ipconfig
• Usage: Displays the current IP address, subnet mask, and default gateway for all network adapters.
• Subcommands:
  • ipconfig /all: Shows detailed information about all network interfaces.
  • ipconfig /release: Releases the current IP address.
  • ipconfig /renew: Renews the IP address.

Ping Command

• Command: ping [hostname/IP]
• Usage: Tests connectivity to a specific IP address or hostname. Useful for diagnosing network issues.
• Example: ping google.com

DNS

• Command: ipconfig /flushdns
• Usage: The command removes all entries from the DNS resolver cache. This means that any previously stored DNS information is deleted.
• Troubleshooting examples:
  1. DNS Issues: If you are experiencing issues accessing websites, such as getting a “Page Not Found” error or being directed to an old IP address, flushing the DNS cache can resolve these problems.
  2. DNS Propagation: If a website has recently changed its IP address (like after a server migration), your computer may still have the old IP address cached. Flushing the DNS cache ensures you get the updated IP address.
  3. Testing Configuration Changes: When you make changes to your DNS settings or configurations, flushing the cache can help you verify that the new settings are being applied.

Manage User Account Policies

• Command: net accounts
• Usage: It provides options for configuring various account settings, particularly those related to password policies and account lockout settings.
• Examples:
  1. Password Policies: Minimum password length, Maximum password age, Minimum password age, Password history
  2. Account Lockout Policies: Account lockout duration, Lockout threshold (number of failed logon attempts before the account is locked), Reset lockout counter (time in minutes before the counter resets)

Group Policy Management

• Command: gpupdate , gpupdate /force
• Usage: It forces the computer to check for updated Group Policy settings and applies them immediately. This is particularly useful in situations where changes have been made to Group Policy Objects (GPOs) and you want to ensure that those changes take effect right away.
• Examples:
  1. Running gpupdate without any options will refresh both user and computer policies.
  2. Running gpupdate /force , forces the application of all Group Policy settings, even those that have not changed. It essentially reapplies all policies.

Network Statistics

• Command: netstat
• Usage: Displays active network connections, routing tables, and network interface statistics.
• Troubleshooting Examples:
  1. Identifying Active Connections: netstat -a : If you cannot connect to a specific service, you can check if the relevant port is listening.
  2. Checking Listening Ports: netstat -an | find "LISTEN" : If a service is not reachable, ensure that the corresponding port is listed as “LISTENING.”
  3. Checking Network Statistics: netstat -s : If you’re experiencing network slowdowns, checking statistics can reveal if there are high error rates or dropped packets.

Task List

• Command: tasklist
• Usage: : Displays a list of currently running processes. It provides information such as the process name, Process ID (PID), session name, session number, and memory usage.
• Troubleshooting Examples:
  1. Identifying Resource-Heavy Processes: By checking the memory usage of each process, you can identify which applications are consuming excessive resources, potentially causing system slowdowns.
  2. Finding Unresponsive Applications: If an application is not responding, you can use tasklist to check if it is still running and identify its PID for termination if necessary.
  3. Diagnosing Application Crashes: If an application crashes frequently, you can track its behavior through tasklist to see if it remains in memory or if multiple instances are running unexpectedly.

System File Checker

• Command: sfc /scannow
• Usage: Scans and repairs corrupted system files. It checks the integrity of protected system files and replaces incorrect versions with correct Microsoft versions.
• Troubleshooting Example:
  1. Restore Corrupted Files: If you’re experiencing system crashes, application errors, or other instability issues, running this command can help restore corrupted files.

Check Disk Utility

• Command: chkdsk [drive:] /f /r
• Usage: Checks the specified disk for errors and attempts to fix them. The /f option fixes errors on the disk, and the /r option locates bad sectors and recovers readable information.
• Troubleshooting Example:
  1. File system errors: If you suspect disk corruption or encounter file system errors, running CHKDSK can identify and resolve these issues.

System Configuration Utility

• Command: msconfig
• Usage: Opens the System Configuration tool, which allows you to manage startup programs, services, and boot options.
• Troubleshooting Example:
  1. Diagnosing Startup Issues: If Windows fails to boot properly or crashes during startup, you can select “Diagnostic startup” from the General tab. This option loads only essential drivers and services, helping to determine if a startup program or service is causing the problem.
  2. Selective Startup: If you suspect that a third-party application or service is causing system instability, you can use “Selective startup” to disable non-essential services and startup items. By gradually enabling them one at a time, you can identify the culprit.
  3. Boot Options: If you’re encountering issues that require safe mode (e.g., malware infection or driver conflicts), you can enable Safe Mode from the Boot tab. This allows you to troubleshoot issues with minimal drivers and services loaded.
  4. Restoring System Configuration: If you’ve made changes that have led to system instability, you can quickly revert to a previous configuration by selecting “Normal startup” to re-enable all services and startup items.

Conclusion

System utilities in Windows are indispensable for troubleshooting because they provide the necessary tools to diagnose, repair, and optimize system performance. By offering insights into system health, managing resources, and allowing for proactive maintenance, these utilities empower users and administrators to maintain a stable and efficient computing environment.