Zeroconf
Encyclopedia
Zero configuration networking (zeroconf), is a set of techniques that automatically creates a usable Internet Protocol
(IP) network without manual operator intervention or special configuration servers.
Zero configuration networking allows devices such as computers and printers to connect to a network automatically. Without zeroconf, a network administrator must set up services, such as Dynamic Host Configuration Protocol
(DHCP) and Domain Name System
(DNS), or configure each computer's network settings manually, which may be difficult and time-consuming.
Zeroconf is built on three core technologies:
and IPv6
have standard methods for address autoconfiguration.
For link-local addressing IPv4 uses the special block 169.254.0.0/16 as described in RFC 3927 while IPv6 hosts use the prefix fe80::/10.
Most IPv4 hosts use link-local addressing (IPv4LL) only as a last resort when a DHCP server is unavailable.
An IPv4 host otherwise uses its DHCP-assigned address for all
communications, global or link-local.
One reason is that IPv4 hosts are not required to support multiple addresses per interface, although many do.
Another is that not every IPv4 host implements distributed name resolution (e.g., multicast DNS
), so discovering the autoconfigured link-local
address of another host on the network can be difficult.
However, discovering the DHCP-assigned address of another host
also requires either distributed name resolution or a unicast DNS server
with this information, and some networks feature DNS servers that are automatically updated with
DHCP-assigned host and address information.
IPv6 hosts are required to support multiple addresses per interface;
moreover, every IPv6 host is required to configure a link-local address even when global addresses are available.
IPv6 hosts may
additionally self-configure one or more global addresses on receipt of one or more router advertisement messages, thus eliminating the need for a DHCP6 server; see RFC 4862.
Both IPv4 and IPv6 hosts may randomly generate the host-specific part of an autoconfigured address.
IPv6 hosts generally combine a prefix of up to 64 bits with a 64-bit EUI-64 derived from the factory-assigned 48-bit IEEE MAC address
. The MAC address have the advantage of being globally unique, a property inherited by the EUI-64.
The host is normally required to ensure, through broadcast queries, that the addresses it generates
are not in use by any other host on the local network.
The technique is called Link-Local address assignment in RFC 3927. However, Microsoft
refers to this as Automatic Private IP Addressing (APIPA) or Internet Protocol Automatic Configuration (IPAC) (supported since at least Windows 98
).
(mDNS) is an open specification, while Microsoft's Link-local Multicast Name Resolution
(LLMNR) is little used and the specification is not an IETF
standards track publication. The latter was published as informational RFC 4795.
The two protocols have minor differences in their approach to name resolution. mDNS allows a network device to choose a domain name in the local
namespace
and announce it using a special multicast IP address. This introduces special semantics for the local domain, which is considered a problem by some members of the IETF. The current LLMNR draft allows a network device to choose any domain name, which is considered a security risk by some members of the IETF. mDNS is compatible with DNS-SD as described in the next section, while LLMNR is not.
(mDNS) is a protocol that uses APIs similar to unicast Domain Name System
but implemented over a multicast protocol. Each computer on the LAN stores its own list of DNS resource records (e.g., A, MX
, SRV
) and joins the mDNS multicast group. When an mDNS client wants to know the IP address of a PC given its name, mDNS client sends a request to a well-known multicast address; the PC with the corresponding A record replies with its IP address. The mDNS multicast address is 224.0.0.251 for IPv4 and ff02::fb for IPv6 link-local addressing.
DNS based Service Discovery (DNS-SD) is the other half of Apple's solution, built on top of the Domain Name System
. It is used in Apple products, many network printers and a number of third party products and applications on various operating systems. The Apple solution uses DNS messages, in contrast to Microsoft's competing technology, SSDP
, which uses HTTP messages. It uses DNS SRV
, TXT, and PTR records to advertise Service Instance Names. The hosts offering services publish details of available services: instance, service type, domain name and optional configuration parameters. Service types are given informally on a first-come basis. A service type registry is maintained and published by DNS-SD.org.
Many Mac OS X
networking clients, such as the Safari browser and the iChat
instant messaging software, use DNS-SD to locate nearby servers. On Windows, some instant messaging and VoIP clients support DNS-SD. Some unix, BSD, and GNU/Linux distributions also include DNS-SD functionality.
mDNS/DNS-SD was developed by Apple Computer
employee Stuart Cheshire
in the company's move from AppleTalk
to IP
.
(SSDP) is a UPnP
protocol, used in Windows XP
and several brands of network equipment. SSDP uses HTTP notification announcements that give a service-type URI
and a Unique Service Name (USN). Service types are regulated by the Universal Plug and Play Steering Committee.
SSDP is supported in many SOHO firewall appliances, where host computers behind it may pierce holes for applications. It is also used in media center
systems, where media exchange between host computers and the media center is facilitated using SSDP.
(SLP), the only protocol for service discovery to have reached the IETF Proposed Standard status, is supported by Hewlett-Packard
's network
printer
s, Novell
, and Sun Microsystems
, but ignored by some other large vendors. SLP is described in RFC 2608 and RFC 3224 and implementations are available for both Solaris
and Linux
.
LLMNR was submitted for official adoption in the DNSEXT IETF working group, however failed to gain consensus and thus has been published as informational RFC only: RFC 4795. Following the failure of LLMNR to become an Internet standard Apple was asked by the IETF to submit the mDNS/DNS-SD specs for publishing as informational RFC as well, given that mDNS/DNS-SD is used much more widely than LLMNR. They are currently published as an Internet Draft
.
RFC 2608, the SLP standard for figuring out where to get services, was published by the SVRLOC IETF working group.
(formerly known as Rendezvous) from Apple Inc., uses multicast DNS and DNS Service Discovery. Apple changed its preferred zeroconf technology from SLP to mDNS and DNS-SD between Mac OS X 10.1 and 10.2, though SLP continues to be supported by Mac OS X.
Apple's mDNSResponder has interfaces for C
and Java
and is available on BSD, Mac OS X, Linux, other POSIX based operating systems and Windows. The Windows downloads are available from Apple's website.
is a Zeroconf implementation for Linux
and BSD
s. It implements IPv4LL, mDNS and DNS-SD. It is part of most Linux distributions, and is installed by default on some. If run in conjunction with nss-mdns it also offers host name resolution.
Avahi also implements binary compatibility libraries that emulate Bonjour and the historical mDNS implementation Howl, so software made to use those implementations can also utilize Avahi through the emulation interfaces.
The above implementations are all stand-alone daemons or plugins for DHCP clients that only deal with link-local IP addresses. Another approach is to include support in new or existing DHCP clients:
Neither of these implementations addresses kernel issues like the broadcasting of ARP
replies or closing of existing network connections.
Internet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
(IP) network without manual operator intervention or special configuration servers.
Zero configuration networking allows devices such as computers and printers to connect to a network automatically. Without zeroconf, a network administrator must set up services, such as 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) and Domain Name System
Domain name system
The Domain Name System is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities...
(DNS), or configure each computer's network settings manually, which may be difficult and time-consuming.
Zeroconf is built on three core technologies:
- Assignment of numeric network addresses for networked devices
- Automatic resolution and distribution of computer hostnameHostnameA hostname is a label that is assigned to a device connected to a computer network and that is used to identify the device in various forms of electronic communication such as the World Wide Web, e-mail or Usenet...
s - Automatic location of network services, such as printing devices
Address selection
Both IPv4IPv4
Internet Protocol version 4 is the fourth revision in the development of the Internet Protocol and the first version of the protocol to be widely deployed. Together with IPv6, it is at the core of standards-based internetworking methods of the Internet...
and IPv6
IPv6
Internet Protocol version 6 is a version of the Internet Protocol . It is designed to succeed the Internet Protocol version 4...
have standard methods for address autoconfiguration.
For link-local addressing IPv4 uses the special block 169.254.0.0/16 as described in RFC 3927 while IPv6 hosts use the prefix fe80::/10.
Most IPv4 hosts use link-local addressing (IPv4LL) only as a last resort when a DHCP server is unavailable.
An IPv4 host otherwise uses its DHCP-assigned address for all
communications, global or link-local.
One reason is that IPv4 hosts are not required to support multiple addresses per interface, although many do.
Another is that not every IPv4 host implements distributed name resolution (e.g., multicast DNS
Multicast DNS
Multicast DNS is a way of using familiar DNS programming interfaces, packet formats and operating , in a small network where no conventional DNS server has been installed....
), so discovering the autoconfigured link-local
address of another host on the network can be difficult.
However, discovering the DHCP-assigned address of another host
also requires either distributed name resolution or a unicast DNS server
with this information, and some networks feature DNS servers that are automatically updated with
DHCP-assigned host and address information.
IPv6 hosts are required to support multiple addresses per interface;
moreover, every IPv6 host is required to configure a link-local address even when global addresses are available.
IPv6 hosts may
additionally self-configure one or more global addresses on receipt of one or more router advertisement messages, thus eliminating the need for a DHCP6 server; see RFC 4862.
Both IPv4 and IPv6 hosts may randomly generate the host-specific part of an autoconfigured address.
IPv6 hosts generally combine a prefix of up to 64 bits with a 64-bit EUI-64 derived from the factory-assigned 48-bit IEEE MAC address
MAC address
A Media Access Control address is a unique identifier assigned to network interfaces for communications on the physical network segment. MAC addresses are used for numerous network technologies and most IEEE 802 network technologies, including Ethernet...
. The MAC address have the advantage of being globally unique, a property inherited by the EUI-64.
The host is normally required to ensure, through broadcast queries, that the addresses it generates
are not in use by any other host on the local network.
The technique is called Link-Local address assignment in RFC 3927. However, Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
refers to this as Automatic Private IP Addressing (APIPA) or Internet Protocol Automatic Configuration (IPAC) (supported since at least Windows 98
Windows 98
Windows 98 is a graphical operating system by Microsoft. It is the second major release in the Windows 9x line of operating systems. It was released to manufacturing on 15 May 1998 and to retail on 25 June 1998. Windows 98 is the successor to Windows 95. Like its predecessor, it is a hybrid...
).
Name resolution
In 2000, Bill Manning and Bill Woodcock described the Multicast Domain Name Service which spawned the implementations by Apple and Microsoft. Both implementations are very similar. Apple's Multicast DNSMulticast DNS
Multicast DNS is a way of using familiar DNS programming interfaces, packet formats and operating , in a small network where no conventional DNS server has been installed....
(mDNS) is an open specification, while Microsoft's Link-local Multicast Name Resolution
Link-local Multicast Name Resolution
The Link Local Multicast Name Resolution is a protocol based on the Domain Name System packet format that allows both IPv4 and IPv6 hosts to perform name resolution for hosts on the same local link...
(LLMNR) is little used and the specification is not an IETF
Internet Engineering Task Force
The Internet Engineering Task Force develops and promotes Internet standards, cooperating closely with the W3C and ISO/IEC standards bodies and dealing in particular with standards of the TCP/IP and Internet protocol suite...
standards track publication. The latter was published as informational RFC 4795.
The two protocols have minor differences in their approach to name resolution. mDNS allows a network device to choose a domain name in the local
.local
local is a pseudo-top-level domain used in multicast domain name service of zero configuration networking discovery protocols.Apple's Bonjour implements mDNS, as does Avahi...
namespace
Namespace (computer science)
A namespace is an abstract container or environment created to hold a logical grouping of unique identifiers or symbols . An identifier defined in a namespace is associated only with that namespace. The same identifier can be independently defined in multiple namespaces...
and announce it using a special multicast IP address. This introduces special semantics for the local domain, which is considered a problem by some members of the IETF. The current LLMNR draft allows a network device to choose any domain name, which is considered a security risk by some members of the IETF. mDNS is compatible with DNS-SD as described in the next section, while LLMNR is not.
Apple's protocol: Multicast DNS/DNS-SD
Multicast DNSMulticast DNS
Multicast DNS is a way of using familiar DNS programming interfaces, packet formats and operating , in a small network where no conventional DNS server has been installed....
(mDNS) is a protocol that uses APIs similar to unicast Domain Name System
Domain name system
The Domain Name System is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities...
but implemented over a multicast protocol. Each computer on the LAN stores its own list of DNS resource records (e.g., A, MX
MX record
A mail exchanger record is a type of resource record in the Domain Name System that specifies a mail server responsible for accepting email messages on behalf of a recipient's domain, and a preference value used to prioritize mail delivery if multiple mail servers are available...
, SRV
SRV record
A Service record is a specification of data in the Domain Name System defining the location, i.e. the hostname and port number, of servers for specified services. It is defined in RFC 2782, and its type code is 33...
) and joins the mDNS multicast group. When an mDNS client wants to know the IP address of a PC given its name, mDNS client sends a request to a well-known multicast address; the PC with the corresponding A record replies with its IP address. The mDNS multicast address is 224.0.0.251 for IPv4 and ff02::fb for IPv6 link-local addressing.
DNS based Service Discovery (DNS-SD) is the other half of Apple's solution, built on top of the Domain Name System
Domain name system
The Domain Name System is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities...
. It is used in Apple products, many network printers and a number of third party products and applications on various operating systems. The Apple solution uses DNS messages, in contrast to Microsoft's competing technology, SSDP
Simple Service Discovery Protocol
The Simple Service Discovery Protocol is a network protocol based on the Internet Protocol Suite for advertisement and discovery of network services and presence information...
, which uses HTTP messages. It uses DNS SRV
SRV record
A Service record is a specification of data in the Domain Name System defining the location, i.e. the hostname and port number, of servers for specified services. It is defined in RFC 2782, and its type code is 33...
, TXT, and PTR records to advertise Service Instance Names. The hosts offering services publish details of available services: instance, service type, domain name and optional configuration parameters. Service types are given informally on a first-come basis. A service type registry is maintained and published by DNS-SD.org.
Many Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...
networking clients, such as the Safari browser and the iChat
IChat
iChat is an instant messaging software application developed by Apple Inc. exclusively for its Mac OS X operating system. It has audio, video and screen-sharing capabilities as well as text messaging...
instant messaging software, use DNS-SD to locate nearby servers. On Windows, some instant messaging and VoIP clients support DNS-SD. Some unix, BSD, and GNU/Linux distributions also include DNS-SD functionality.
mDNS/DNS-SD was developed by Apple Computer
Apple Computer
Apple Inc. is an American multinational corporation that designs and markets consumer electronics, computer software, and personal computers. The company's best-known hardware products include the Macintosh line of computers, the iPod, the iPhone and the iPad...
employee Stuart Cheshire
Stuart Cheshire
Stuart Cheshire is the author of Bolo, a networked tank game, originally written for the BBC Micro and later ported to the Apple Macintosh....
in the company's move from AppleTalk
AppleTalk
AppleTalk is a proprietary suite of protocols developed by Apple Inc. for networking computers. It was included in the original Macintosh released in 1984, but is now unsupported as of the release of Mac OS X v10.6 in 2009 in favor of TCP/IP networking...
to IP
Internet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
.
Microsoft's protocol: UPnP SSDP
Simple Service Discovery ProtocolSimple Service Discovery Protocol
The Simple Service Discovery Protocol is a network protocol based on the Internet Protocol Suite for advertisement and discovery of network services and presence information...
(SSDP) is a UPnP
Universal Plug and Play
Universal Plug and Play is a set of networking protocols for primarily residential networks without enterprise class devices that permits networked devices, such as personal computers, printers, Internet gateways, Wi-Fi access points and mobile devices to seamlessly discover each other's presence...
protocol, used in Windows XP
Windows XP
Windows XP is an operating system produced by Microsoft for use on personal computers, including home and business desktops, laptops and media centers. First released to computer manufacturers on August 24, 2001, it is the second most popular version of Windows, based on installed user base...
and several brands of network equipment. SSDP uses HTTP notification announcements that give a service-type URI
Uniform Resource Identifier
In computing, a uniform resource identifier is a string of characters used to identify a name or a resource on the Internet. Such identification enables interaction with representations of the resource over a network using specific protocols...
and a Unique Service Name (USN). Service types are regulated by the Universal Plug and Play Steering Committee.
SSDP is supported in many SOHO firewall appliances, where host computers behind it may pierce holes for applications. It is also used in media center
Home theater PC
A Home Theater PC or Media Center appliance is a convergence device that combines some or all the capabilities of a personal computer with a software application that supports video, photo, music playback, and sometimes video recording functionality...
systems, where media exchange between host computers and the media center is facilitated using SSDP.
Efforts toward an IETF standard protocol
Service Location ProtocolService Location Protocol
The Service Location Protocol is a service discovery protocol that allows computers and other devices to find services in a local area network without prior configuration. SLP has been designed to scale from small, unmanaged networks to large enterprise networks...
(SLP), the only protocol for service discovery to have reached the IETF Proposed Standard status, is supported by Hewlett-Packard
Hewlett-Packard
Hewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...
's 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....
printer
Computer printer
In computing, a printer is a peripheral which produces a text or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most new printers, a...
s, Novell
Novell
Novell, Inc. is a multinational software and services company. It is a wholly owned subsidiary of The Attachmate Group. It specializes in network operating systems, such as Novell NetWare; systems management solutions, such as Novell ZENworks; and collaboration solutions, such as Novell Groupwise...
, and Sun Microsystems
Sun Microsystems
Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...
, but ignored by some other large vendors. SLP is described in RFC 2608 and RFC 3224 and implementations are available for both Solaris
Solaris Operating System
Solaris is a Unix operating system originally developed by Sun Microsystems. It superseded their earlier SunOS in 1993. Oracle Solaris, as it is now known, has been owned by Oracle Corporation since Oracle's acquisition of Sun in January 2010....
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...
.
Standardization
RFC 3927, a standard for choosing addresses for networked items, was published in March 2005 by the Zeroconf IETF working group, which included individuals from Apple, Sun, and Microsoft.LLMNR was submitted for official adoption in the DNSEXT IETF working group, however failed to gain consensus and thus has been published as informational RFC only: RFC 4795. Following the failure of LLMNR to become an Internet standard Apple was asked by the IETF to submit the mDNS/DNS-SD specs for publishing as informational RFC as well, given that mDNS/DNS-SD is used much more widely than LLMNR. They are currently published as an Internet Draft
Internet Draft
Internet Drafts is a series of working documents published by the IETF. Typically, they are drafts for RFCs, but may be other works in progress not intended for publication as RFCs. It is considered inappropriate to rely on Internet Drafts for reference purposes...
.
RFC 2608, the SLP standard for figuring out where to get services, was published by the SVRLOC IETF working group.
Security issues
Because mDNS operates under a different trust model than unicast DNS—trusting the entire network rather than a designated DNS server—it is vulnerable to spoofing attacks by any system within the multicast IP range. Like SNMP and many other network management protocols, it can also be used by attackers to quickly gain detailed knowledge of the network and its machines.Apple Bonjour
BonjourBonjour (software)
In computing, Bonjour is Apple Inc.'s trade name for its implementation of Zeroconf, a group of technologies that includes service discovery, address assignment, and name resolution...
(formerly known as Rendezvous) from Apple Inc., uses multicast DNS and DNS Service Discovery. Apple changed its preferred zeroconf technology from SLP to mDNS and DNS-SD between Mac OS X 10.1 and 10.2, though SLP continues to be supported by Mac OS X.
Apple's mDNSResponder has interfaces for C
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
and Java
Java (programming language)
Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...
and is available on BSD, Mac OS X, Linux, other POSIX based operating systems and Windows. The Windows downloads are available from Apple's website.
Avahi
AvahiAvahi (software)
Avahi is a free zeroconf implementation, including a system for multicast DNS/DNS-SD service discovery. It is licensed under the GNU Lesser General Public License ....
is a Zeroconf implementation for 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...
and BSD
Berkeley Software Distribution
Berkeley Software Distribution is a Unix operating system derivative developed and distributed by the Computer Systems Research Group of the University of California, Berkeley, from 1977 to 1995...
s. It implements IPv4LL, mDNS and DNS-SD. It is part of most Linux distributions, and is installed by default on some. If run in conjunction with nss-mdns it also offers host name resolution.
Avahi also implements binary compatibility libraries that emulate Bonjour and the historical mDNS implementation Howl, so software made to use those implementations can also utilize Avahi through the emulation interfaces.
Link-local IPv4 addresses
There are some implementations available:- Windows and Mac OS have both supported link-local addresses since 1998. Apple released its open-source implementation in the DarwinDarwin (operating system)Darwin is an open source POSIX-compliant computer operating system released by Apple Inc. in 2000. It is composed of code developed by Apple, as well as code derived from NeXTSTEP, BSD, and other free software projects....
bootp package. - AvahiAvahi (software)Avahi is a free zeroconf implementation, including a system for multicast DNS/DNS-SD service discovery. It is licensed under the GNU Lesser General Public License ....
contains an implementation of IPv4LL in the avahi-autoipd tool. - zcip (Zero-Conf IP)
- BusyBoxBusyBoxBusyBox provides several stripped-down Unix tools in a single executable. It runs in a variety of POSIX environments such as Linux, Android, FreeBSD and others, such as proprietary kernels, although many of the tools it provides are designed to work with interfaces provided by the Linux kernel. It...
can embed a simple IPv4LL implementation - Stablebox, a fork from Busybox, offers a slightly modified IPv4LL implementation named llad.
- zeroconf, a package based on Simple IPv4LL, a shorter implementation by Arthur van Hoff.
The above implementations are all stand-alone daemons or plugins for DHCP clients that only deal with link-local IP addresses. Another approach is to include support in new or existing DHCP clients:
- Elvis Pfützenreuter has written a patch for the uDHCP client/server.
- dhcpcd is an opensource DHCP client for LinuxLinuxLinux 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...
and BSD that includes IPv4LL support. It is included as standard in NetBSDNetBSDNetBSD 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,...
.
Neither of these implementations addresses kernel issues like the broadcasting of ARP
Address Resolution Protocol
Address Resolution Protocol is a telecommunications protocol used for resolution of network layer addresses into link layer addresses, a critical function in multiple-access networks. ARP was defined by RFC 826 in 1982. It is Internet Standard STD 37...
replies or closing of existing network connections.
See also
- Avahi (software)Avahi (software)Avahi is a free zeroconf implementation, including a system for multicast DNS/DNS-SD service discovery. It is licensed under the GNU Lesser General Public License ....
- Sleep Proxy ServiceSleep Proxy ServiceApple's Bonjour Sleep Proxy service is an open sourcecomponent of zero configuration networking, designed to assist in reducing power consumption of networked electronic devices. A device acting as a sleep proxy server will respond to Multicast DNS queries for another, compatible device which has...
, also known as Bonjour Sleep Proxy - Universal Plug and PlayUniversal Plug and PlayUniversal Plug and Play is a set of networking protocols for primarily residential networks without enterprise class devices that permits networked devices, such as personal computers, printers, Internet gateways, Wi-Fi access points and mobile devices to seamlessly discover each other's presence...
- Wireless Zero ConfigurationWireless Zero ConfigurationWireless Zero Configuration , also known as Wireless Auto Configuration, or WLAN AutoConfig is a wireless connection management utility included with Microsoft Windows XP and later operating systems as a service that dynamically selects a wireless network to connect to based on a user's preferences...
External links
- JmDNS, a pure Java implementation of mDNS/DNS-SD
- pyZeroConf, a pure PythonPython (programming language)Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Python claims to "[combine] remarkable power with very clear syntax", and its standard library is large and comprehensive...
implementation of mDNS/DNS-SD - Mono.Zeroconf, a cross platform (Linux, Windows, Mac), unified Mono/.NET library for Zeroconf, supporting both Bonjour and Avahi
- WxServDisc, a cross-platform wxWidgets-based service discovery module without external dependencies.
- Multicast DNS Specification
- DNS-Based Service Discovery Specification
- Zeroconf.org - Stuart Cheshire's page, including internet drafts.
- dns-sd.org DNS based Service Discovery
- multicastdns.org Multicast DNS
- "Understanding Zeroconf and Multicast DNS", December 2002 article, slightly outdated, on the O'Reilly Network.
- AIR Wiki : ZeroconfTechnologies
- Charter of the DNSEXT working group, which coordinates LLMNR standardization
- RFC 2608, Service Location Protocol, Version 2
- Zero Configuration Networking: The Definitive Guide, by Daniel Steinberg and Stuart Cheshire, O'Reilly
- Zeroconf tech talk by Stuart Cheshire to Google engineers.