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A network technician is checking a computer to see if the DHCP client is working correctly. The technician issues the ipconfig /all command. Which two parameters should the technician review? (Choose two.)

A network technician is checking a computer to see if the DHCP client is working correctly. The technician issues the ipconfig /all command. Which two parameters should the technician review? (Choose two.)

  • description
  • default gateway
  • host name
  • media state
  • subnet mask

When a network technician is checking if the DHCP client is functioning correctly on a computer, one of the most effective tools at their disposal is the ipconfig /all command. This command provides detailed information about the network configuration, including parameters essential for DHCP operation. In this case, the two most critical parameters to review are the default gateway and the subnet mask. Both of these parameters are crucial for ensuring that the DHCP client has received the correct configuration from the DHCP server and that the computer can communicate properly within the network and beyond.

Let’s dive deeper into why the default gateway and subnet mask are key indicators of a correctly working DHCP client and how they contribute to overall network functionality.

1. Default Gateway

The default gateway is a critical parameter in any network configuration. It specifies the IP address of the router or network device that connects the local network to other networks, including the internet. In most cases, the default gateway is the IP address of the router that forwards traffic from the local network to external networks.

Why It Matters:

  • Network Communication: The default gateway allows the computer to communicate with devices outside its local subnet. Without a valid default gateway, the computer would be limited to communicating only with devices on the same subnet, and it would not be able to reach external networks, including the internet. This makes it a critical parameter for determining if the DHCP client has received a valid network configuration.
  • DHCP Role: The DHCP server is responsible for assigning the default gateway to DHCP clients. If the DHCP client is working correctly, it should have a valid default gateway listed in the results of the ipconfig /all command. If the default gateway is missing, incorrect, or set to 0.0.0.0, this could indicate an issue with the DHCP server or with the DHCP client’s ability to obtain a proper lease.
  • Troubleshooting Connectivity Issues: When a technician sees that the computer cannot access external networks, one of the first things they should check is the default gateway. A missing or incorrect default gateway might prevent the computer from routing traffic correctly, especially when trying to reach websites or external servers. By reviewing the default gateway, the technician can quickly determine if the DHCP client has configured this parameter correctly.

Example Scenario:

If a technician runs the ipconfig /all command and finds that the default gateway is set to 0.0.0.0 or is absent altogether, it indicates that the DHCP client did not receive proper network configuration from the DHCP server. This might point to a DHCP server issue, a network misconfiguration, or even a local issue on the computer itself.

2. Subnet Mask

The subnet mask is another essential parameter that the DHCP client must obtain correctly. It defines the range of IP addresses within the local network (or subnet) and specifies which portion of the IP address identifies the network and which portion identifies individual hosts within the network. Essentially, the subnet mask divides the IP address into the network and host portions.

Why It Matters:

  • Local Network Communication: The subnet mask helps the computer determine whether a destination IP address is within the same local network or on a different network. If the destination is within the same subnet, the computer can communicate directly with it. However, if the destination is outside the subnet, the computer needs to forward the traffic to the default gateway. A valid and correctly configured subnet mask ensures that the computer can differentiate between local and external addresses properly.
  • DHCP Role: The DHCP server is responsible for assigning the subnet mask to DHCP clients. If the DHCP client receives an incorrect or invalid subnet mask, the computer may not be able to communicate with other devices on the network, or it may route traffic incorrectly. For example, if the subnet mask is too restrictive or too broad, the computer might fail to recognize that certain devices are part of its local network.
  • Troubleshooting Incorrect Network Configuration: When reviewing the output of the ipconfig /all command, the technician should look for the correct subnet mask that matches the network’s configuration. An incorrect subnet mask can lead to a variety of issues, such as being unable to reach other devices on the same network or incorrectly routing traffic to the default gateway even when it should remain local. Therefore, checking the subnet mask is a key step in verifying that the DHCP client has correctly obtained all necessary network configuration details.

Example Scenario:

Imagine a network where the correct subnet mask is 255.255.255.0, which allows for 254 usable IP addresses on the local network. If the DHCP client mistakenly receives a subnet mask of 255.255.0.0, the computer will believe that all devices with IP addresses in a much larger range are part of the local network, leading to routing errors and communication issues.

Why the Other Parameters Are Less Critical:

  • Host Name: While the host name is important for identifying the computer within the network, it is not directly related to the operation of the DHCP client. The host name can be manually configured or dynamically assigned, but it does not affect the computer’s ability to communicate with the network or obtain a proper IP configuration from the DHCP server.
  • Description: The description parameter typically refers to the description of the network interface, such as “Ethernet Adapter” or “Wi-Fi Adapter.” This parameter is useful for identifying which network interface is being used, but it does not provide any information about the functionality of the DHCP client or the correctness of the IP configuration.
  • Media State: The media state indicates whether the network interface is connected or disconnected. While this is important for ensuring that the computer is physically connected to the network, it does not provide any details about the DHCP client’s configuration. A connected media state simply means that the network interface is active, but it does not guarantee that the DHCP client has obtained a valid IP configuration.

Conclusion:

When checking whether the DHCP client is functioning correctly, the default gateway and subnet mask are the two most critical parameters to review. The default gateway ensures that the computer can communicate with external networks, while the subnet mask ensures proper communication within the local network. Both of these parameters are automatically assigned by the DHCP server, and if either is missing or incorrect, the technician can immediately identify a problem with the DHCP client or the DHCP server. By focusing on these parameters, the technician can quickly troubleshoot and resolve network connectivity issues, ensuring that the computer is correctly configured to communicate with the local network and beyond.