ImRAD DHCP - Revision history

Shin at 02:14, 9 August 2023

2023-08-09T02:14:45Z

Shin at 07:27, 29 June 2021

2021-06-29T07:27:10Z

Shin: /* DHCP Overview */

2021-06-29T07:25:09Z

DHCP Overview

Shin: /* DHCP Overview */

2021-06-29T07:22:21Z

DHCP Overview

Shin: /* DHCP Overview */

2021-06-29T07:21:45Z

DHCP Overview

Shin: /* DHCPv6https://en.wikipedia.org/wiki/DHCPv6 */

2021-06-04T02:24:55Z

DHCPv6https://en.wikipedia.org/wiki/DHCPv6

Shin at 06:36, 1 June 2021

2021-06-01T06:36:47Z

Shin at 06:36, 1 June 2021

2021-06-01T06:36:35Z

Shin at 06:34, 1 June 2021

2021-06-01T06:34:57Z

Shin: /* Force Release */

2021-05-24T01:31:19Z

Force Release

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 ===== [[DHCP Option configuration | DHCP Option]]=====
 ===== [[DHCP Log | Log - Lease, PostDHCP]]=====
 ===== Settings=====

@@ Line 15: / Line 15: @@
 ==== DHCPv4<ref name="dhcp-wiki" /><ref>https://tools.ietf.org/html/rfc2131</ref> ====
-[[File:800px-DHCP_session.svg.png|200px|thumb|DHCPv4]]
+[[File:800px-DHCP_session.svg.png|200px|thumb|DHCPv4<ref name="dhcp-wiki" />]]
-[[File:1280px-Dhcp-client-state-diagram.svg.png|500px|thumb|DHCPv4 client state-transition diagram]]
+[[File:1280px-Dhcp-client-state-diagram.svg.png|500px|thumb|DHCPv4 client state-transition diagram<ref name="dhcp-wiki" />]]
 The DHCP employs a connectionless service model, using the User Datagram Protocol (UDP). It is implemented with two UDP port numbers for its operations which are the same as for the bootstrap protocol (BOOTP). UDP port number 67 is the destination port of a server, and UDP port number 68 is used by the client.

@@ Line 10: / Line 10: @@
 A DHCP client typically queries for this information immediately after booting, and periodically thereafter before the expiration of the information. When a DHCP client refreshes an assignment, it initially requests the same parameter values, but the DHCP server may assign a new address based on the assignment policies set by administrators.
-On large networks that consist of multiple links, a single DHCP server may service the entire network when aided by DHCP relay agents located on the interconnecting routers. Such agents relay messages between DHCP clients and DHCP servers located on different subnets.
+On large networks that consist of multiple links, a single DHCP server may service the entire network when aided by DHCP relay agents located on the interconnecting routers. Such agents relay messages between DHCP clients and DHCP servers located on different subnets.<ref name="dhcp-wiki">https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol</ref>
 The imRAD provides both the DHCPv4 and DHCPv6 services.
-==== DHCPv4<ref>https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol</ref><ref>https://tools.ietf.org/html/rfc2131</ref> ====
+==== DHCPv4<ref name="dhcp-wiki" /><ref>https://tools.ietf.org/html/rfc2131</ref> ====
 [[File:800px-DHCP_session.svg.png|200px|thumb|DHCPv4]]
 [[File:1280px-Dhcp-client-state-diagram.svg.png|500px|thumb|DHCPv4 client state-transition diagram]]

@@ Line 1: / Line 1: @@
 __FORCETOC__
 === DHCP Overview ===
-The Dynamic Host Configuration Protocol (DHCP) is a network management protocol used on Internet Protocol (IP) local area networks for automatically assigning IP addresses and other communication parameters to devices connected to the network.
+The Dynamic Host Configuration Protocol (DHCP) is a network management protocol used on Internet Protocol (IP) local area networks for automatically assigning IP addresses and other communication parameters to devices connected to the network.<br>
 A device connected to the network requests an IP address using the DHCP protocol, the server assigns a unique address to the device. A device configured to use dynamic (DHCP) addressing that is connected to a different network will be assigned an address on that network without needing to be reconfigured.

@@ Line 1: / Line 1: @@
 __FORCETOC__
 === DHCP Overview ===
-The Dynamic Host Configuration Protocol (DHCP) is a network management protocol used on Internet Protocol (IP) local area networks. A DHCP server must be present on the network. A device connected to the network requests an IP address from the DHCP server using the DHCP protocol, the server assigns a unique address to the device, A device configured to use dynamic (DHCP) addressing that is connected to a different network will be assigned an address on that network without needing to be reconfigured.
+The Dynamic Host Configuration Protocol (DHCP) is a network management protocol used on Internet Protocol (IP) local area networks for automatically assigning IP addresses and other communication parameters to devices connected to the network.
-DHCP operates based on the client–server model. When a computer or other device connects to a network, the DHCP client software sends a DHCP broadcast query requesting the necessary information. Any DHCP server on the network may service the request.<br>
+DHCP operates based on the client-server model. When a computer or other device connects to a network, the DHCP client software sends a DHCP broadcast query requesting the necessary information. Any DHCP server on the network may service the request.<br>
 The DHCP server manages a pool of IP addresses and information about client configuration parameters such as default gateway, domain name, the name servers, and time servers. <br>
 On receiving a DHCP request, the DHCP server may respond with specific information for each client, as previously configured by an administrator, or with a specific address and any other information valid for the entire network and for the time period for which the allocation (lease) is valid.
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 On large networks that consist of multiple links, a single DHCP server may service the entire network when aided by DHCP relay agents located on the interconnecting routers. Such agents relay messages between DHCP clients and DHCP servers located on different subnets.
-The imRAD provides both the DHCPv4 and DHCPv6 service.
+The imRAD provides both the DHCPv4 and DHCPv6 services.
 ==== DHCPv4<ref>https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol</ref><ref>https://tools.ietf.org/html/rfc2131</ref> ====

@@ Line 56: / Line 56: @@
-==== DHCPv6<ref>https://en.wikipedia.org/wiki/DHCPv6</ref> ====
+==== DHCPv6<ref>https://en.wikipedia.org/wiki/DHCPv6</ref><ref>https://datatracker.ietf.org/doc/html/rfc8415</ref> ====
-The Dynamic Host Configuration Protocol version 6 (DHCPv6) is a network protocol for configuring Internet Protocol version 6 (IPv6) hosts with IP addresses, IP prefixes and other configuration data required to operate in an IPv6 network. It is the IPv6 equivalent of the Dynamic Host Configuration Protocol for IPv4.<br>
+The Dynamic Host Configuration Protocol version 6 (DHCPv6) is a network protocol for configuring Internet Protocol version 6 (IPv6) hosts with IP addresses, IP prefixes, and other configuration data required to operate in an IPv6 network. It is the IPv6 equivalent of the Dynamic Host Configuration Protocol for IPv4.<br>
 IPv6 global unicast addresses can be configured dynamically, without any manual configuration. There are [[SLAAC, Stateful, and stateless DHCPv6 | three ways(i.e. SLAAC, Stateless DHCPv6, and Stateful DHCPv6) ]] to dynamically configure the global unicast address.
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 Relay agents exchange messages with servers to relay messages between clients and servers that are not connected to the same link.
 [[File:dhcp6_relay.jpg|420px|DHCPv6 Relay Agent Communication<br>Rick Graziani, IPv6 Fundamentals, ciscocompress, Figure 9-4, 2013]]
 === Force Release ===

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 The DHCP employs a connectionless service model, using the User Datagram Protocol (UDP). It is implemented with two UDP port numbers for its operations which are the same as for the bootstrap protocol (BOOTP). UDP port number 67 is the destination port of a server, and UDP port number 68 is used by the client.
-DHCP operations fall into four phases: server discovery, IP lease offer, IP lease request, and IP lease acknowledgement. These stages are often abbreviated as DORA for discovery, offer, request, and acknowledgement.
+DHCP operations fall into four phases: server discovery, IP lease offer, IP lease request, and IP lease acknowledgment. These stages are often abbreviated as DORA for discovery, offer, request, and acknowledgment.
-The DHCP operation begins with clients broadcasting a request. If the client and server are on different subnets, a DHCP Helper or DHCP Relay Agent may be used. Clients requesting renewal of an existing lease may communicate directly via UDP unicast, since the client already has an established IP address at that point.
+The DHCP operation begins with clients broadcasting a request. If the client and server are on different subnets, a DHCP Helper or DHCP Relay Agent may be used. Clients requesting the renewal of an existing lease may communicate directly via UDP unicast since the client already has an established IP address at that point.
 ===== Discovery =====
-The client broadcasts a DHCPDISCOVER message on its local physical subnet. The DHCPDISCOVER message MAY include options that suggest values for the network address and lease duration. BOOTP relay agents may pass the message on to DHCP servers not on the same physical subnet.
+The client broadcasts a DHCPDISCOVER message on its local physical subnet. The DHCPDISCOVER message MAY include options that suggest values for the network address and lease duration. BOOTP relay agents may pass the message on to DHCP servers, not on the same physical subnet.
 ===== Offer =====
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 ===== Acknowledgement(ACK) / Non-Acknowledgement(NAK)=====
-When the DHCP server receives the DHCPREQUEST message from the client, the configuration process enters its final phase. The acknowledgement phase involves sending a DHCPACK packet to the client. This packet includes the lease duration and any other configuration information that the client might have requested. At this point, the IP configuration process is completed.
+When the DHCP server receives the DHCPREQUEST message from the client, the configuration process enters its final phase. The acknowledgment phase involves sending a DHCPACK packet to the client. This packet includes the lease duration and any other configuration information that the client might have requested. At this point, the IP configuration process is completed.
 After the client obtains an IP address, it should probe the newly received address(e.g. with ARP Address Resolution Protocol) to prevent address conflicts caused by overlapping address pools of DHCP servers.
-If the client's request is invalid (e.g., the client has moved to a new subnet or the client requested with an invalid 'requested IP address'), the server responds to the client with a DHCPNAK message.
+If the client's request is invalid (e.g., the client has moved to a new subnet or the client requested with an invalid "requested IP address"), the server responds to the client with a DHCPNAK message.
 If the client receives a DHCPNAK message, the client restarts the configuration process.

@@ Line 84: / Line 84: @@
 === Force Release ===
-This feature can deallocate IP addresses prior to their lease time.
+This feature can deallocate IP addresses prior to their [[DHCPv4 Lease Time |lease time]] or [[DHCPv6 lifetime]].
 For example, When a host was assigned "1.1.1.10" and the host moves to another VLAN, the host will be assigned a new IP address and the old IP address(i.e. 1.1.1.10) will remain in lease status until the lease time expires. In this case, none of the hosts uses the "1.1.1.10" and the address is not assigned to any host because it is still in lease status.
 Especially under the wireless environment, The bigger the lease time, the more such garbage addresses.