Editing Dynamic Host Configuration Protocol (section)

===DHCP message types===
This table lists the DHCP message types.
These codes are the value in the DHCP extension 53, shown in the table above.

{| class="wikitable sortable"
|+  DHCP message types
|-
! Code !! Name !! Length !! RFC
|-
| 1 || DHCPDISCOVER || 1 octet || {{Sum RFC|2132|plain=yes}}{{Ref RFC|2132|rsection=9.6}}
|-
| 2 || DHCPOFFER || 1 octet || {{Sum RFC|2132|plain=yes}}
|-
| 3 || DHCPREQUEST || 1 octet || {{Sum RFC|2132|plain=yes}}
|-
| 4 || DHCPDECLINE || 1 octet || {{Sum RFC|2132|plain=yes}}
|-
| 5 || DHCPACK || 1 octet || {{Sum RFC|2132|plain=yes}}
|-
| 6 || DHCPNAK || 1 octet || {{Sum RFC|2132|plain=yes}}
|-
| 7 || DHCPRELEASE || 1 octet || {{Sum RFC|2132|plain=yes}}
|-
| 8 || DHCPINFORM || 1 octet || {{Sum RFC|2132|plain=yes}}
|-
| 9 || DHCPFORCERENEW ||  1 octet || {{Sum RFC|3203|plain=yes}}{{Ref RFC|3203|rsection=4}}
|-
| 10 || DHCPLEASEQUERY ||  1 octet || {{Sum RFC|4388|plain=yes}}{{Ref RFC|4388|rsection=6.1}}
|-
| 11 || DHCPLEASEUNASSIGNED ||  1 octet || {{Sum RFC|4388|plain=yes}}
|-
| 12 || DHCPLEASEUNKNOWN ||  1 octet || {{Sum RFC|4388|plain=yes}}
|-
| 13 || DHCPLEASEACTIVE ||  1 octet || {{Sum RFC|4388|plain=yes}}
|-
| 14 || DHCPBULKLEASEQUERY ||  1 octet || {{Sum RFC|6926|plain=yes}}{{Ref RFC|6926|rsection=6.2.1}}
|-
| 15 || DHCPLEASEQUERYDONE ||  1 octet || {{Sum RFC|6926|plain=yes}}
|-
| 16 || DHCPACTIVELEASEQUERY ||  1 octet || {{Sum RFC|7724|plain=yes}}{{Ref RFC|7724|rsection=5.2.1}}
|-
| 17 || DHCPLEASEQUERYSTATUS ||  1 octet || {{Sum RFC|7724|plain=yes}}
|-
| 18 || DHCPTLS ||  1 octet || {{Sum RFC|7724|plain=yes}}
|}

====Client vendor identification====
An option exists to identify the vendor and functionality of a DHCP client. The information is a [[Variable-length code|variable-length string]] of characters or octets which has a meaning specified by the vendor of the DHCP client. One method by which a DHCP client can communicate to the server that it is using a certain type of hardware or firmware is to set a value in its DHCP requests called the Vendor Class Identifier (VCI) (Option 60).

The value to which this option is set gives the DHCP server a hint about any required extra information that this client needs in a DHCP response. Some types of [[set-top boxes]] set the VCI to inform the DHCP server about the hardware type and functionality of the device. An [[Aruba Networks|Aruba]] campus [[wireless access point]], for example, supplies value 'ArubaAP' as option 60 in its DHCPDISCOVER message.<ref name="option60">{{cite web|title=Aruba DHCP Option 60|date=7 October 2020 |url=https://the-ethernets.com/2020/10/aruba-dhcp-option-60/}}</ref> The DHCP server can then augment its DHCPOFFER with an IP address of an Aruba [[wireless controller]] in option 43, so the access point knows where to register itself.

Setting a VCI by the client allows a DHCP server to differentiate between client machines and process the requests from them appropriately.