Dhcpd
Encyclopedia
dhcpd is a common name for the daemon
that allows a server
to provide a Dynamic Host Configuration Protocol
(DHCP) service to a network
.
Clients
may solicit an IP address
(IP) from a DHCP server when they need one. The DHCP server then offers the "lease" of an IP address to the client, which the client is free to request or ignore. If the client requests it and the server acknowledges it, then the client is permitted to use that IP address for the "lease time" specified by the server. At some point before the lease expires, the client must re-request the same IP address if it wishes to continue to use it.
Issued IP addresses are tracked by dhcpd through a record in the dhcpd.leases file. This allows the server to maintain state over restarts of the dhcp service, which could otherwise lead to duplicate IP addresses being issued when server issued the same IP address again while another client still has the right to use it.
A reference implementation
of dhcpd is developed by the Internet Systems Consortium
and is supported on Solaris, FreeBSD
, OpenBSD
, NetBSD
and Linux
.
Daemon (computer software)
In Unix and other multitasking computer operating systems, a daemon is a computer program that runs as a background process, rather than being under the direct control of an interactive user...
that allows a server
Server (computing)
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...
to provide a Dynamic Host Configuration Protocol
Dynamic Host Configuration Protocol
The Dynamic Host Configuration Protocol is a network configuration protocol for hosts on Internet Protocol networks. Computers that are connected to IP networks must be configured before they can communicate with other hosts. The most essential information needed is an IP address, and a default...
(DHCP) service to a network
Computer network
A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....
.
Clients
Client (computing)
A client is an application or system that accesses a service made available by a server. The server is often on another computer system, in which case the client accesses the service by way of a network....
may solicit an IP address
IP address
An Internet Protocol address is a numerical label assigned to each device participating in a computer network that uses the Internet Protocol for communication. An IP address serves two principal functions: host or network interface identification and location addressing...
(IP) from a DHCP server when they need one. The DHCP server then offers the "lease" of an IP address to the client, which the client is free to request or ignore. If the client requests it and the server acknowledges it, then the client is permitted to use that IP address for the "lease time" specified by the server. At some point before the lease expires, the client must re-request the same IP address if it wishes to continue to use it.
Issued IP addresses are tracked by dhcpd through a record in the dhcpd.leases file. This allows the server to maintain state over restarts of the dhcp service, which could otherwise lead to duplicate IP addresses being issued when server issued the same IP address again while another client still has the right to use it.
A reference implementation
Reference implementation
In the software development process, a reference implementation is the standard from which all other implementations, with their attendant customizations, are measured, and to which all improvements are added...
of dhcpd is developed by the Internet Systems Consortium
Internet Systems Consortium
Internet Systems Consortium, Inc., also known as ISC, is a Delaware-registered, 501 public benefit non-profit corporation dedicated to supporting the infrastructure of the universal connected self-organizing Internet by developing and maintaining core production quality software, protocols, and...
and is supported on Solaris, FreeBSD
FreeBSD
FreeBSD is a free Unix-like operating system descended from AT&T UNIX via BSD UNIX. Although for legal reasons FreeBSD cannot be called “UNIX”, as the direct descendant of BSD UNIX , FreeBSD’s internals and system APIs are UNIX-compliant...
, OpenBSD
OpenBSD
OpenBSD is a Unix-like computer operating system descended from Berkeley Software Distribution , a Unix derivative developed at the University of California, Berkeley. It was forked from NetBSD by project leader Theo de Raadt in late 1995...
, NetBSD
NetBSD
NetBSD is a freely available open source version of the Berkeley Software Distribution Unix operating system. It was the second open source BSD descendant to be formally released, after 386BSD, and continues to be actively developed. The NetBSD project is primarily focused on high quality design,...
and Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
.
External links
- Configuring dhcpd on a wireless access point
- dhcpd section in the ISC website
- [ftp://ftp.isc.org/isc/dhcp/ Official FTP repository]
- dhcpd man page
- dhcp.conf man page