How DHCP Clients Request Previous IP Address

B.

DHCP (Dynamic Host Configuration Protocol) is a network protocol that enables a server to automatically assign IP addresses and other network configuration parameters to client devices. When a DHCP client requests an IP address, it can request its previously used IP address as well.

To request its previously used IP address, the DHCP client includes the IP address in the DHCP REQUEST packet as an option, which is encapsulated within the DHCP OPTIONS field. The DHCP Option 50 (Requested IP Address) is used by the client to request a particular IP address from the DHCP server.

Therefore, option B is the correct answer to the question. The DHCP Option 50 field is used by the client to request a specific IP address from the DHCP server. If the server has assigned the requested IP address to another client, it will respond with a DHCP NAK (Negative Acknowledgment) message, and the client will have to request a different IP address.

Option A (CIADDR field) is used by the client to specify its current IP address when renewing its lease with the DHCP server. Option C (YIADDR field) is used by the server to assign an IP address to the client. Option D (source IP address of the UDP/53 wrapper packet) is the IP address of the client's network interface and is not related to DHCP request. Option E is incorrect, as the client can request its last IP address using the DHCP Option 50.