DHCP Vendor Class Identifier: Understanding the MSFT 50
Background of DHCP Message Exchange
The Dynamic Host Configuration Protocol (DHCP) is a network protocol that assigns IP addresses and other network configuration parameters to devices on a network. DHCP is a client-server protocol that uses User Datagram Protocol (UDP) for communication. The DHCPv4 client, such as a computer or smartphone, sends a DHCPDISCOVER message to a DHCPv4 server, such as a Wi-Fi router, to request an IP address. The DHCPv4 server then responds with a DHCPOFFER message, which includes the IP address and other configuration parameters that the client needs to configure its network interface.
The DHCPv4 client can also send a DHCPREQUEST message to request additional configuration parameters, such as the subnet mask and default gateway. The DHCPv4 server then responds with a DHCPACK message, which contains the requested configuration parameters. The DHCPv4 client then configures its network interface with the IP address and other configuration parameters that it received from the DHCPv4 server.
Vendor Class Identifier
The Vendor Class Identifier (VCI) is a DHCP option that allows the DHCPv4 client to specify its vendor or the version of the operating system that it is running. The VCI is typically used by the DHCPv4 server to provide vendor-specific configuration parameters to the DHCPv4 client. For example, a DHCPv4 client that is running Microsoft Windows XP might send a VCI of "MSFT 50" to the DHCPv4 server. The DHCPv4 server can then use this information to provide the DHCPv4 client with configuration parameters that are specific to Microsoft Windows XP.
The VCI is a string that can be up to 255 characters long. The VCI is typically specified in the DHCPDISCOVER message that the DHCPv4 client sends to the DHCPv4 server. The DHCPv4 server can use the VCI to provide vendor-specific configuration parameters to the DHCPv4 client in the DHCPOFFER message that it sends to the DHCPv4 client.
Root Cause of DHCP Status Removed Due to Conflict
The DHCP status Removed Due to Conflict can occur when two or more DHCPv4 clients on the network try to use the same IP address. This can happen if the DHCPv4 clients are using the same VCI and the DHCPv4 server is not configured to handle duplicate VCI requests. When this happens, the DHCPv4 server will remove the duplicate IP address from the DHCP address pool and assign a new IP address to the DHCPv4 client that requested it.
To avoid the DHCP status Removed Due to Conflict, the DHCPv4 server should be configured to handle duplicate VCI requests. This can be done by configuring the DHCPv4 server to use a unique VCI for each DHCPv4 client or by configuring the DHCPv4 server to ignore duplicate VCI requests.
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