DHCP Vendor Class ID Mismatch with Wireshark

Understanding Vendor Class Identifiers in DHCP

The Vendor Class Identifier (VCI) is a field in the DHCP protocol that allows a device to identify itself to a DHCP server. Each type of device, such as a Windows computer or an Android device, has a specific VCI assigned to it by the manufacturer.

Issue Identification

During a DHCP process between devices and a Wi-Fi router DHCP server, it was observed using Wireshark that the VCI for a Windows 8 client was "MSFT 5 0", while the VCI for an Android device was "dhcpcd-5 5 6". However, the client running Windows 8 should have a VCI of "MSFT 98". This mismatch indicated that the client was not correctly identifying itself to the DHCP server.

Implications and Potential Causes

This VCI mismatch can lead to issues with DHCP lease negotiation and IP address assignment. It may also affect the device's ability to access the network or access certain network resources.

The cause of this issue could be related to incorrect driver settings, outdated software, or other factors affecting the DHCP client implementation on the Windows 8 device.

Conclusion

To resolve this issue, it is recommended to check the device's network settings, update drivers and software, and consult with the device manufacturer for specific troubleshooting steps.