DHCPREQUEST

As explained in Acing the CCNA Exam: Volume 2 Advanced Networking and Security

DHCPREQUEST is a DHCP client message that requests an offered address or renews an existing lease.

DHCPREQUEST is the client message that accepts a DHCP server’s offered IP address during the DORA leasing process. It is normally broadcast to 255.255.255.255 and sourced from 0.0.0.0. section 4.1.1 section 4.4

Place DHCPREQUEST in the operational sequence:

• DISCOVER locates DHCP servers and announces the client’s need for an address. section 4.1.1
• OFFER proposes an IP address and other configuration parameters. section 4.4
• REQUEST accepts the offered address, typically selecting the first offer when multiple servers respond. section 4.1.1 section 4.4
• ACK confirms and finalizes the lease, after which the client can use the leased parameters. section 4.4

Figure 4.2 Leasing an IPv4 address via DHCP (the DORA process): (1) DISCOVER from client to server, (2) OFFER from server to client, (3) REQUEST from client to server, (4) ACK from server to client.

Follow the four-message IPv4 exchange visually: DISCOVER, OFFER, REQUEST, and ACK. section 4.1.1

How Acing the CCNA Exam: Volume 2 Advanced Networking and Security covers it

How deep it goes

Defines the message’s sequence role and addressing, but does not detail its packet fields or renewal behavior.

Examples

Shows a client broadcasting DHCPREQUEST after receiving an OFFER in the DORA exchange.

What it assumes

Recognize basic client-server communication and the DISCOVER, OFFER, REQUEST, and ACK sequence.

What you can do after

Evaluate DHCP exchanges by identifying the offer-acceptance step and the client’s UDP port 68.

How it connects

Connects DHCPDISCOVER, DHCPOFFER, DHCPACK, DHCP, UDP, and dynamic IP addressing.

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Related concepts

• request messagekind of · An HTTP request is a message sent by a client to a server that specifies a method and target and may include headers and a body.

This explainer was generated by Manning's knowledge graph from the text of Acing the CCNA Exam: Volume 2 Advanced Networking and Security. The section links point to the parts of the book it draws on.