Using ipconfig to View and Modify Network Information on Windows

Objective

Learn how to use the ipconfig command on a Windows system to view and modify network information. This lab covers basic usage, advanced options, and practical troubleshooting scenarios.

Prerequisites

1. Windows Operating System:
   • A Windows machine with administrative privileges.
2. Basic Understanding of Networking:
   • Familiarity with concepts like IP addresses, subnet masks, and default gateways.
3. Access to Command Prompt:
   • Open Command Prompt by pressing Win + R, typing cmd, and pressing Enter.

Step 1: Viewing Basic Network Information

1. Open Command Prompt.
2. Run the ipconfig command:

   ipconfig
   

3. Analyze the output:
   • IPv4 Address: The primary address of the system (e.g., 192.168.1.100).
   • Subnet Mask: Defines the network portion of the IP address (e.g., 255.255.255.0).
   • Default Gateway: The router IP address used to access external networks (e.g., 192.168.1.1).

Step 2: Viewing Detailed Network Information

1. Use the /all flag to display detailed information about all network adapters:

   ipconfig /all
   

2. Review additional details:
   • Physical Address: The MAC address of the adapter.
   • DHCP Enabled: Indicates whether the system is using DHCP to obtain an IP address.
   • DNS Servers: Lists the configured DNS server addresses.

   Example Output:

   Ethernet adapter Ethernet:
      IPv4 Address. . . . . . . . . . . : 192.168.1.100
      Subnet Mask . . . . . . . . . . . : 255.255.255.0
      Default Gateway . . . . . . . . . : 192.168.1.1
      DNS Servers . . . . . . . . . . . : 8.8.8.8
   

Step 3: Releasing and Renewing IP Addresses

Releasing the Current IP Address

1. Run the following command to release the current IP:

   ipconfig /release
   

2. Verify that the adapter no longer has an assigned IP.

Renewing the IP Address

1. Run the following command to obtain a new IP:

   ipconfig /renew
   

2. Verify that the adapter has received a new IP address.

   Tip: Use this when troubleshooting DHCP-related issues.

Step 4: Flushing the DNS Cache

1. Clear the DNS resolver cache to remove outdated entries:

   ipconfig /flushdns
   

2. Verify that the cache was cleared:

   ipconfig /displaydns
   

   Insight: Flushing the DNS cache resolves issues with accessing recently changed domains.

Step 5: Displaying Specific Adapter Information

1. View information for a specific adapter by filtering the output:

   ipconfig | findstr /C:"IPv4"
   

2. Combine ipconfig with findstr to customize your queries.

   Tip: Use this to quickly locate details without sifting through long outputs.

Step 6: Setting a Static IP Address

1. Open the Network and Sharing Center:
   • Right-click the network icon in the system tray and select Open Network & Internet settings.
2. Navigate to the adapter settings:
   • Click Change adapter options > Right-click your network adapter > Select Properties.
3. Set a static IP:
   • Double-click Internet Protocol Version 4 (TCP/IPv4).
   • Choose Use the following IP address and enter:
     • IP Address: e.g., 192.168.1.150
     • Subnet Mask: 255.255.255.0
     • Default Gateway: e.g., 192.168.1.1
     • DNS Servers: e.g., 8.8.8.8 and 8.8.4.4

   Tip: Use static IPs for servers or devices that require consistent addresses.

Step 7: Troubleshooting Network Issues

1. No Internet Access:
   • Use ipconfig /release and ipconfig /renew to reset your IP.
   • Verify the default gateway and DNS server settings.
2. Incorrect DNS Resolution:
   • Run ipconfig /flushdns to clear cached entries.
   • Test domain resolution using ping <domain>.
3. No IP Address Assigned:
   • Ensure the network adapter is enabled:

     netsh interface show interface
     

   • Enable the adapter if necessary:

     netsh interface set interface "<Adapter Name>" enable
     

Additional Tips and Insights

1. Combine ipconfig with Other Tools:
   • Use ping, tracert, or nslookup alongside ipconfig for comprehensive troubleshooting.
2. Automate Tasks:
   • Create batch scripts for repetitive tasks like flushing DNS or releasing/renewing IPs.
3. IPv6 Support:
   • View IPv6 details using ipconfig /all. Disable IPv6 if not needed for simpler configurations.
4. DNS Over HTTPS (DoH):
   • Check if your network supports DoH by reviewing your DNS resolver settings.

Key Takeaways

1. The ipconfig command is a fundamental tool for viewing and modifying network configurations on Windows.
2. Understanding its various options enhances your ability to troubleshoot common networking issues.
3. Combining ipconfig with other utilities provides a comprehensive approach to diagnosing connectivity problems.