Dynamic Host Configuration Protocol (DHCP) is a protocol used by networked devices (clients) to obtain the parameters necessary for operation in an Internet Protocol network. This protocol reduces system administration workload, allowing devices to be added to the network with little or no manual configurations. In computing and telecommunications, the transport layer is the second highest layer in the four and five layer TCP/IP reference models, where it responds to service requests from the application layer and issues service requests to the Internet layer. ... The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite. ... User Datagram Protocol (UDP) is one of the core protocols of the Internet protocol suite. ... The Datagram Congestion Control Protocol (DCCP) is a message-oriented transport layer protocol that is currently under development in the IETF. Applications that might make use of DCCP include those with timingconstraints on the delivery of data such that reliable in-order delivery, when combined with congestion control, is likely... In the field of computer networking, the IETF Signaling Transport (SIGTRAN) working group defined the Stream Control Transmission Protocol (SCTP) as a transport layer protocol in 2000. ... The Resource ReSerVation Protocol (RSVP), described in RFC 2205, is a Transport layer protocol designed to reserve resources across a network for an integrated services Internet. ... Network congestion avoidance is a process used in computer networks to avoid congestion. ... The network layer is third layer out of seven in OSI model and it is the third layer out of five in TCP/IP model. ... The Internet Protocol (IP) is a data-oriented protocol used for communicating data across a packet-switched internetwork. ... Internet Protocol version 4 (IPv4) is the fourth iteration of the Internet Protocol (IP) and it is the first version of the protocol to be widely deployed. ... Internet Protocol version 6 (IPv6) is a network layer for packet-switched internetworks. ... The Open Shortest Path First (OSPF) protocol is a hierarchical interior gateway protocol (IGP) for routing in Internet Protocol, using a link-state in the individual areas that make up the hierarchy. ... Is Is is Yeah Yeah Yeahs third EP, to be released on July 24, 2007. ... IPsec (IP security) is a suite of protocols for securing Internet Protocol (IP) communications by authenticating and/or encrypting each IP packet in a data stream. ... In computer networking, the Address Resolution Protocol (ARP) is the standard method for finding a hosts hardware address when only its network layer address is known. ... Reverse Address Resolution Protocol (RARP) is a network layer protocol used to obtain an IP address for a given hardware address (such as an Ethernet address). ... This article is chiefly about the Routing Information Protocol (RIP) for the Internet Protocol, but also discusses some other routing information protocols. ... The Internet Control Message Protocol (ICMP) is one of the core protocols of the Internet protocol suite. ... The ICMP for IPv6 (Internet Control Message Protocol Version 6) is an integral part of the IPv6 architecture and must be completely supported by all IPv6 implementations. ... The Internet Group Management Protocol (IGMP) is a communications protocol used to manage the membership of Internet Protocol multicast groups. ... The data link layer is layer two of the seven-layer OSI model as well as of the five-layer TCP/IP reference model. ... IEEE 802. ... The IEEE 802. ... Wi-Fi (IPA: ) is the common name for a popular wireless technology used in home networks, mobile phones, video games and more. ... Official WiMax logo WiMAX, the Worldwide Interoperability for Microwave Access, is a telecommunications technology aimed at providing wireless data over long distances in a variety of ways, from point-to-point links to full mobile cellular type access. ... Asynchronous Transfer Mode (ATM) is a cell relay, packet switching network and data link layer protocol which encodes data traffic into small (53 bytes; 48 bytes of data and 5 bytes of header information) fixed-sized cells. ... Dynamic synchronous Transfer Mode , or DTM for short, is a network protocol. ... Token-Ring local area network (LAN) technology was developed and promoted by IBM in the early 1980s and standardised as IEEE 802. ... Ethernet is a large, diverse family of frame-based computer networking technologies that operate at many speeds for local area networks (LANs). ... In computer networking, fiber-distributed data interface (FDDI) is a standard for data transmission in a local area network that can extend in range up to 200 km (124 miles). ... In the context of computer networking, frame relay consists of an efficient data transmission technique used to send digital information quickly and cheaply. ... General Packet Radio Service (GPRS) is a Mobile Data Service available to users of Global System for Mobile Communications (GSM) and IS-136 mobile phones. ... Evolution-Data Optimized or Evolution-Data only, abbreviated as EV-DO or EVDO and often EV, is one telecommunications standard for the wireless transmission of data through radio signals, typically for broadband Internet access. ... High-Speed Packet Access (HSPA) is a collection of mobile telephony protocols that extend and improve the performance of existing UMTS protocols. ... High-Level Data Link Control (HDLC) is a bit-oriented synchronous data link layer protocol developed by the International Organization for Standardization (ISO). ... In computing, the Point-to-Point Protocol, or PPP, is commonly used to establish a direct connection between two nodes. ... The Point-to-Point Tunneling Protocol (PPTP) is a method for implementing virtual private networks. ... In computer networking, the Layer 2 Tunneling Protocol (L2TP) is a tunneling protocol used to support virtual private networks (VPNs). ... ISDN redirects here. ... ARCNET (also CamelCased as ARCnet, an acronym from Attached Resource Computer NETwork) is a local area network (LAN) protocol, similar in purpose to Ethernet or Token Ring. ... Link Layer Topology Discovery (LLTD) is a licensed data link layer protocol for network topology discovery and quality of service diagnostics, developed by Microsoft as part of their Windows Rally set of technologies. ... This article does not cite any references or sources. ... The Ethernet physical layer is the physical layer component of the Ethernet standard. ... RS-232 (also referred to as EIA RS-232C or V.24) is a standard for serial binary data interchange between a DTE (Data terminal equipment) and a DCE (Data communication equipment). ... Synchronous optical networking (SONET) and Synchronous Digital Hierarchy (SDH), are two closely related multiplexing protocols for transferring multiple digital bit streams using lasers or light-emitting diodes (LEDs) over the same optical fiber. ... There are very few or no other articles that link to this one. ... Optical fibers An optical fiber (or fibre) is a glass or plastic fiber designed to guide light along its length. ... Coaxial Cable For the weapon, see coaxial weapon. ... 25 Pair Color Code Chart 10BASE-T UTP Cable Twisted pair cabling is a common form of wiring in which two conductors are wound around each other for the purposes of cancelling out electromagnetic interference known as crosstalk. ... DHCP in the context of computing can stand for: Dynamic Host Configuration Protocol — one of the protocols in the TCP/IP networking suite Decentralized Hospital Computer Program of the United States Department of Veterans Affairs Category: ... The Internet Protocol (IP) is a data-oriented protocol used for communicating data across a packet-switched internetwork. ...

Applicability

Dynamic Host Configuration Protocol is a way to manage network parameter assignment from a single DHCP server, or a group of DHCP servers arranged in a fault-tolerant manner. Even in small networks, Dynamic Host Configuration Protocol is useful because it can make it easy to add new machines to the local network.

DHCP is also recommended even in the case of servers whose addresses rarely change, so that if a server needs to be readdressed (RFC2071), changes can be made in as few places as possible. For devices such as routers and firewalls, that should not use DHCP, it can be useful to put Trivial File Transfer Protocol (TFTP) or SSH servers on the same machine that runs DHCP, which also serves to centralize administration. In information technology, a server is an application or device that performs services for connected clients as part of a client-server architecture. ... This article is about a computer networking device. ... Firewall may refer to: Firewall (construction), a physical barrier inside a building or vehicle, designed to limit the spread of fire, heat and structural collapse Firewall (networking), a logical barrier designed to prevent unauthorized or unwanted communications between sections of a computer network Firewall (film), a 2006 action film written... Trivial File Transfer Protocol (TFTP) is a very simple file transfer protocol, with the functionality of a very basic form of FTP; it was first defined in 1980. ... SSH redirects here. ...

DHCP can be used to directly assign addresses to servers and desktop machines, and, through a Point-to-Point Protocol (PPP) proxy, to dialup and broadband on-demand hosts, as well as for residential Network address translation (NAT) gateways and routers. DHCP is generally not appropriate for infrastructure such as non-edge routers and DNS servers. In computing, the Point-to-Point Protocol, or PPP, is commonly used to establish a direct connection between two nodes. ... In computer networking, Network Address Translation (NAT, also known as Network Masquerading, Native Address Translation or IP Masquerading) is a technique of transceiving network traffic through a router that involves re-writing the source and/or destination IP addresses and usually also the TCP/UDP port numbers of IP packets... In telecommunications, the term gateway has the following meanings: In a communications network, a network node equipped for interfacing with another network that uses different protocols. ... The Domain Name System (DNS) associates various sorts of information with domain names; most importantly, it serves as the phone book for the Internet by translating human-readable computer hostnames, e. ...

History

DHCP emerged as a standard protocol in October 1993 as defined in RFC 1531, succeeding the BOOTP protocol. The next update, RFC 2131 released in 1997 is the current DHCP definition. The latest proposed standard for DHCP over IPv6 (DHCPv6) can be found in RFC 3315. In computing, BOOTP, short for Bootstrap Protocol, is a UDP network protocol used by a network client to obtain its IP address atically. ... DHCPv6 is the Dynamic Host Configuration Protocol for IPv6. ...

Basic protocol operation

The Dynamic Host Configuration Protocol (DHCP) automates the assignment of IP addresses, subnet masks, default gateway, and other IP parameters. ^[1]

When a DHCP-configured client (be it a computer or any other network-aware device) connects to a network, the DHCP client sends a broadcast query requesting necessary information from a DHCP server. The DHCP server manages a pool of IP addresses and information about client configuration parameters such as the default gateway, the domain name, the DNS servers, other servers such as time servers, and so forth. Upon receipt of a valid request the server will assign the computer an IP address, a lease (the length of time for which the allocation is valid), and other IP configuration parameters, such as the subnet mask and the default gateway. The query is typically initiated immediately after booting and must be completed before the client can initiate IP-based communication with other hosts. Routing Schemes anycast broadcast multicast unicast In computer networking, broadcasting refers to transmitting a packet that will be received (conceptually) by every device on the network. ... A subnet mask is a method of hiding or masking the network address portion of an IP address. ... A default gateway is a node on a computer network that serves as an access point to another network. ... In computing, booting (booting up) is a bootstrapping process that starts operating systems when the user turns on a computer system. ... The Internet Protocol (IP) is a data-oriented protocol used for communicating data across a packet-switched internetwork. ...

DHCP provides three modes for allocating IP addresses. The best-known mode is dynamic, in which the client is provided a "lease" on an IP address for a period of time. Depending on the stability of the network, this could range from hours (a wireless network at an airport) to months (for desktops in a wired lab). At any time before the lease expires, the DHCP client can request renewal of the lease on the current IP address. A properly-functioning client will use the renewal mechanism to maintain the same IP address throughout its connection to a single network, otherwise it may risk losing its lease while still connected, thus disrupting network connectivity while it renegotiates with the server for its original or a new IP address.

The two other modes for allocation of IP addresses are automatic (also known as DHCP Reservation), in which the address is permanently assigned to a client, and manual, in which the address is selected by the client (manually by the user or any other means) and the DHCP protocol messages are used to inform the server that the address has been allocated.

The automatic and manual methods are generally used when finer-grained control over IP address is required (typical of tight firewall setups), although typically a firewall will allow access to the range of IP addresses that can be dynamically allocated by the DHCP server. This article is about the network security device. ...

The process of address allocation is known as ROSA. R-Request, O-Offer, S-Send, A-Accept.

Security

Having been standardized before network security became a significant issue, the basic DHCP protocol includes no security features, and is potentially vulnerable to two types of attacks:^[2]

• Unauthorized DHCP Servers: as you cannot specify the server you want, an unauthorized server can respond to client requests, sending client network configuration values that are beneficial to the attacker. As an example, a hacker can hijack the DHCP process to configure clients to use a malicious DNS server or router (see also DNS cache poisoning).

• Unauthorized DHCP Clients: By masquerading as a legitimate client, an unauthorized client can gain access to network configuration and an IP address on a network it should otherwise not be allowed to use. Also, by flooding the DHCP server with requests for IP addresses, it is possible for an attacker to exhaust the pool of available IP addresses, disrupting normal network activity (a denial of service attack).

To combat these threats RFC 3118 ("Authentication for DHCP Messages") introduced authentication information into DHCP messages allowing clients and servers to reject information from invalid sources. Although support for this protocol is widespread, a large number of clients and servers still do not fully support authentication, thus forcing servers to support clients that do not support this feature. As a result, other security measures are usually implemented around the DHCP server (such as IPsec) to ensure that only authenticated clients and servers are granted access to the network. A rogue DHCP server is a DHCP server on a network which is not under the administrative control of the network staff. ... The Domain Name System (DNS) associates various sorts of information with domain names; most importantly, it serves as the phone book for the Internet by translating human-readable computer hostnames, e. ... DNS cache poisoning is a technique that tricks a DNS server into believing it has received authentic information when, in reality, it has not. ... In the context of network security, a spoofing attack is a situation in which one person or program successfully masquerades as another by falsifying data and thereby gaining an illegitimate advantage. ... A denial-of-service attack (also, DoS attack) is an attack on a computer system or network that causes a loss of service to users, typically the loss of network connectivity and services by consuming the bandwidth of the victim network or overloading the computational resources of the victim system. ... IPsec (IP security) is a suite of protocols for securing Internet Protocol (IP) communications by authenticating and/or encrypting each IP packet in a data stream. ...

Wherever possible, DHCP-assigned addresses should be dynamically linked to a secure DNS server, to allow troubleshooting by name rather than by a potentially unknown address. Effective DHCP-DNS linkage requires having a file of either MAC addresses or local names that will be sent to DNS that uniquely identifies physical hosts, IP addresses, and other parameters such as the default gateway, subnet mask, and IP addresses of DNS servers from a DHCP server. The DHCP server ensures that all IP addresses are unique, i.e., no IP address is assigned to a second client while the first client's assignment is valid (its lease has not expired). Thus IP address pool management is done by the server and not by a network administrator.. A default gateway is a node on a computer network that serves as an access point to another network. ... A graphic representation of relationships and source of the various variables representing a chunk of C subnets In computer networks, a subnetwork or subnet is a range of logical addresses within the address space that is assigned to an organization. ... The Domain Name System (DNS) associates various sorts of information with domain names; most importantly, it serves as the phone book for the Internet by translating human-readable computer hostnames, e. ...

IP address allocation

Depending on implementation, the DHCP server may have three methods of allocating IP-addresses, plus a fourth mode of operation ("manual") in which the client (rather than the DHCP server) assigns an IP address. (WARNING--the terminology below differs from the terminology above in Basic Control Operation):

• dynamic allocation: A network administrator assigns a range of IP addresses to DHCP, and each client computer on the LAN has its IP software configured to request an IP address from the DHCP server during network initialization. The request-and-grant process uses a lease concept with a controllable time period, allowing the DHCP server to reclaim (and then reallocate) IP addresses that are not renewed (dynamic re-use of IP addresses).
• automatic allocation: The DHCP server permanently assigns a free IP address to a requesting client from the range defined by the administrator. This is like dynamic allocation, but the DHCP server keeps a table of past IP address assignments, so that it can preferentially assign to a client the same IP address that the client previously had.
• static allocation: The DHCP server allocates an IP address based on a table with MAC address/IP address pairs, which are manually filled in (perhaps by a network administrator). Only requesting clients with a MAC address listed in this table will be allocated an IP address. This feature (which is not supported by all routers) is variously called "Static DHCP Assignment" (by DD-WRT), "fixed-address" (by the dhcpd documentation), "DHCP reservation" or "Static DHCP" (by Cisco/Linksys), and "IP reservation" or "MAC/IP binding" (by various other router manufacturers).
• manual allocation: The DHCP server does not assign the IP address; instead, the client is configured with a user-specified static IP address.

Many DHCP servers can manage hosts by more than one of the above methods. For example, the known hosts on the network can be assigned an IP address based on their MAC address (static allocation) whereas "guest" computers (such as laptops via WiFi) are allocated a temporary IP address out of a pool compatible with the network to which they're attached (dynamic allocation). The terms network administrator, network specialist and network analyst designate job positions of engineers involved in computer networks, the people who carry out network administration. ... The Internet Protocol (IP) is a data-oriented protocol used for communicating data across a packet-switched internetwork. ... In information technology, a server is an application or device that performs services for connected clients as part of a client-server architecture. ... In computer networking a Media Access Control address (MAC address) or Ethernet Hardware Address (EHA) or hardware address or adapter address is a quasi-unique identifier attached to most network adapters (NICs). ... An IP address (or Internet Protocol address) is a unique address that certain electronic devices use in order to identify and communicate with each other on a computer network utilizing the Internet Protocol standard (IP)—in simpler terms, a computer address. ... The terms network administrator, network specialist and network analyst designate job positions of engineers involved in computer networks, the people who carry out network administration. ... DD-WRT was originally designed for routers like this Linksys WRT54G, but will now run on a variety of routers DD-WRT is free Linux-based firmware for several wireless routers, most notably the Linksys WRT54G (including the WRT54GL and WRT54GS). ... A 802. ...

DHCP and firewalls

Firewalls usually have to permit DHCP traffic explicitly. Specification of the DHCP client-server protocol describes several cases when packets must have the source address of 0x00000000 or the destination address of 0xffffffff. Anti-spoofing policy rules and tight inclusive firewalls often stop such packets. Multi-homed DHCP servers require special consideration and further complicate configuration. This article is about the network security device. ... In the context of network security, a spoofing attack is a situation in which one person or program successfully masquerades as another by falsifying data and thereby gaining an illegitimate advantage. ... Multihoming is a technique to increase the reliability of the internet connection of an IP network. ...

To allow DHCP, network administrators need to allow several types of packets through the server-side firewall. All DHCP packets travel as UDP datagrams; all client-sent packets have source port 68 and destination port 67; all server-sent packets have source port 67 and destination port 68. For example, a server-side firewall should allow the following types of packets: User Datagram Protocol (UDP) is one of the core protocols of the Internet protocol suite. ...

• Incoming packets from 0.0.0.0 or dhcp-pool to dhcp-ip
• Incoming packets from any address to 255.255.255.255
• Outgoing packets from dhcp-ip to dhcp-pool or 255.255.255.255

where dhcp-ip represents any address configured on a DHCP server host and dhcp-pool stands for the pool from which a DHCP server assigns addresses to clients

Example in ipfw firewall

To give an idea of how a configuration would look in production, the following rules for a server-side ipfirewall to allow DHCP traffic through. Dhcpd operates on interface rl0 and assigns addresses from 192.168.0.0/24 : Not to be confused with IPFW, Indiana University—Purdue University Fort Wayne. ...

 pass udp from 0.0.0.0,192.168.0.0/24 68 to me 67 in recv rl0 pass udp from any 68 to 255.255.255.255 67 in recv rl0 pass udp from me 67 to 192.168.0.0/24,255.255.255.255 68 out xmit rl0 

Example in Cisco IOS Extended ACL

The following entries are valid on a Cisco 3560 switch with enabled DHCP service. The ACL is applied to a routed interface, 10.32.73.129, on input. The subnet is 10.32.73.128/26. In computer security, an access control list (ACL) is a list of permissions attached to an object. ...

 10 permit udp host 0.0.0.0 eq bootpc host 10.32.73.129 eq bootps 20 permit udp 10.32.73.128 0.0.0.63 eq bootpc host 10.32.73.129 eq bootps 30 permit udp any eq bootpc host 255.255.255.255 eq bootps 

Technical details

Schema of a typical DHCP session

DHCP uses the same two IANA assigned ports as BOOTP: 67/udp for the server side, and 68/udp for the client side. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... The Internet Assigned Numbers Authority (IANA) is the entity that oversees global IP address allocation, DNS root zone management, and other Internet protocol assignments. ... In computing, BOOTP, short for Bootstrap Protocol, is a UDP network protocol used by a network client to obtain its IP address automatically. ... In computer networking, the term server-side refers to operations that are performed by the server in a client-server relationship. ... Client/Server is a network application architecture which separates the client (usually the graphical user interface) from the server. ...

DHCP operations fall into four basic phases. These phases are IP discovery, IP lease offer, IP request, and IP lease acknowledgement.

After the client obtained an IP address, the client may start an address resolution (ARP) query to prevent IP conflicts caused by address pool overlapping of DHCP servers. In computer networking, the Address Resolution Protocol (ARP) is the standard method for finding a hosts hardware address when only its network layer address is known. ...

DHCP discovery

The client broadcasts on the physical subnet to find available servers. Network administrators can configure a local router to forward DHCP packets to a DHCP server on a different subnet. This client-implementation creates a UDP packet with the broadcast destination of 255.255.255.255 or subnet broadcast address. User Datagram Protocol (UDP) is one of the core protocols of the Internet protocol suite. ...

A client can also request its last-known IP address (in the example below, 192.168.1.100). If the client is still in a network where this IP is valid, the server might grant the request. Otherwise, it depends whether the server is set up as authoritative or not. An authoritative server will deny the request, making the client ask for a new IP immediately. A non-authoritative server simply ignores the request, leading to an implementation-dependent timeout for the client to give up on the request and ask for a new IP address.

DHCP offers

When a DHCP server receives an IP lease request from a client, it extends an IP lease offer. This is done by reserving an IP address for the client and sending a DHCPOFFER message across the network to the client. This message contains the client's MAC address, followed by the IP address that the server is offering, the subnet mask, the lease duration, and the IP address of the DHCP server making the offer.

The server determines the configuration, based on the client's hardware address as specified in the CHADDR field. Here the server, 192.168.1.1, specifies the IP address in the YIADDR field.

DHCP requests

When the client PC receives an IP lease offer, it must tell all the other DHCP servers that it has accepted an offer. To do this, the client broadcasts a DHCPREQUEST message containing the IP address of the server that made the offer. When the other DHCP servers receive this message, they withdraw any offers that they might have made to the client. They then return the address that they had reserved for the client back to the pool of valid addresses that they can offer to another computer. Any number of DHCP servers can respond to an IP lease request, but the client can only accept one offer per network interface card.

DHCP acknowledgement

When the DHCP server receives the DHCPREQUEST message from the client, it initiates the final phase of the configuration process. This 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 complete.

The server acknowledges the request and sends the acknowledgement to the client. The system as a whole expects the client to configure its network interface with the supplied options.

User Datagram Protocol (UDP) is one of the core protocols of the Internet protocol suite. ... In computing, BOOTP, short for Bootstrap Protocol, is a UDP network protocol used by a network client to obtain its IP address automatically. ... In computing, BOOTP, short for Bootstrap Protocol, is a UDP network protocol used by a network client to obtain its IP address automatically. ... In computing, BOOTP, short for Bootstrap Protocol, is a UDP network protocol used by a network client to obtain its IP address automatically. ... In computing, BOOTP, short for Bootstrap Protocol, is a UDP network protocol used by a network client to obtain its IP address automatically. ...

DHCP information

The client to the DHCP server: either to request more information than the server sent with the original DHCPACK; or to repeat data for a particular application - for example, browsers use DHCP Inform to obtain web proxy settings via WPAD. Such queries do not cause the DHCP server to refresh the IP expiry time in its database. The Web Proxy Autodiscovery Protocol (WPAD) is a method used by clients to locate a proxy auto-config file automatically and use this to configure the browsers web proxy settings. ...

DHCP releasing

The client sends a request to the DHCP server to release the DHCP and the client unconfigures its IP address. As clients usually do not know when users may unplug them from the network, the protocol does not mandate the sending of DHCP Release.

Client configuration parameters

A DHCP server can provide optional configuration parameters to the client. RFC 2132 describes the available DHCP options defined by Internet Assigned Numbers Authority (IANA) - DHCP and BOOTP PARAMETERS. The Internet Assigned Numbers Authority (IANA) is the entity that oversees global IP address allocation, DNS root zone management, and other Internet protocol assignments. ...

Options

To identify the vendor and functionality of a DHCP client. The information is a variable-length string of characters or octets which has a meaning specified by the vendor of the DHCP client. One method that a DHCP client can utilize to 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). This method allows a DHCP server to differentiate between the two kinds of client machines and process the requests from the two types of modems appropriately. Some types of set-top boxes also set the VCI (Option 60) to inform the DHCP server about the hardware type and functionality of the device. The value that this option is set to gives the DHCP server a hint about any required extra information that this client needs in a DHCP response.

See also

• Bootstrap Protocol (BOOTP)
• DHCP snooping
• IP address, especially Static and dynamic IP addresses
• Peg DHCP RFC 2322
• Preboot Execution Environment (PXE)
• Reverse Address Resolution Protocol (RARP)
• Rogue DHCP
• udhcpc - light version for embedded systems
• Web Proxy Autodiscovery Protocol (WPAD)
• Zeroconf, Zero Configuration Networking

In computing, BOOTP, short for Bootstrap Protocol, is a UDP network protocol used by a network client to obtain its IP address atically. ... When DHCP servers are allocating IP addresses to the clients on the LAN, DHCP snooping can be configured to bolster the security on the LAN to only allow clients with specific IP/MAC addresses to have access to the network. ... An IP address (or Internet Protocol address) is a unique address that certain electronic devices use in order to identify and communicate with each other on a computer network utilizing the Internet Protocol standard (IP)—in simpler terms, a computer address. ... This article or section does not cite any references or sources. ... Peg DHCP implemented: Pegs and network information used at What the Hack 2005. ... The Preboot Execution Environment (PXE, aka Pre-Execution Environment, or pixie) is an environment to bootstrap computers using a network interface card independently of available data storage devices (like hard disks) or installed operating systems. ... Reverse Address Resolution Protocol (RARP) is a network layer protocol used to obtain an IP address for a given hardware address (such as an Ethernet address). ... A rogue DHCP server is a DHCP server on a network which is not under the administrative control of the network staff. ... There are very few or no other articles that link to this one. ... The Web Proxy Autodiscovery Protocol (WPAD) is a method used by clients to locate a proxy auto-config file automatically and use this to configure the browsers web proxy settings. ... Zeroconf or Zero Configuration Networking is a set of techniques that automatically create a usable IP network without configuration or special servers. ...

References

External links

• An Introduction to Dynamic Host Configuration Protocol
• RFC 2131 - Dynamic Host Configuration Protocol
• RFC 2132 - DHCP Options and BOOTP Vendor Extensions
• DHCP RFC - Dynamic Host Configuration Protocol RFC's (IETF)
• DHCP Server Security - This article looks at the different types of threats faced by DHCP servers and counter-measures for mitigating these threats.
• RFC 4242 - Information Refresh Time Option for Dynamic Host Configuration Protocol for IPv6
• DHCP Sequence Diagram - This sequence diagram covers several scenarios of DHCP operation.
• RFC 3046, Recommended Operation for Switches Running Relay Agent and Option 82 describes how DHCP option 82 works
• RFC 3942 - Reclassifying Dynamic Host Configuration Protocol Version Four (DHCPv4) Options
• RFC 4361 - Node-specific Client Identifiers for Dynamic Host Configuration Protocol Version Four (DHCPv4)
• DHCP Protocol Messages - A good description of the individual DHCP protocol messages.
• ISC DHCP - Internet Services Consortium's open source DHCP implementation.
• Tiny DHCP Server for Windows - Free, easy to use DHCP service for Windows system.
• BusyBox uDHCP client and server for embedded systems.