Zeroconf

Zeroconf or Zero Configuration Networking is the name of a whole of technologies making it possible several computers to communicate without configuration.

The goal is to obtain a network functional IP without dependence of an infrastructure (waiter DHCP, waiter DNS, etc) or of an expertise network. Zeroconf was created by Stuart Cheshire, former employee of Apple, when this company passed from Appletalk to IP. It from now on is adopted by many manufacturers of apparatuses network.

For example, the printers in network do not have a keyboard or screen to enter an address IP, a footbridge and a mask of sub-network, they must then car-be configured to be usable.

Components

Zeroconf manages four aspects:

Dynamic allocation of IP address without waiter DHCP
Resolution of names and IP addresses without waiter DNS
Search for services without directory
Allowance of IP addresses multicast without waiter MADCAP

Dynamic allocation of address IP

For IPv4, there exists a standard for the dynamic allocation of IP addresses in the beach 169.254.0.0 /16. See RFC 3927 published in March 2005.

For IPv6, the dynamic allocation of IP addresses is planned in the protocol (see RFC 2461).

Resolution of names

Two solutions exist:

Apple Hello (mDNS), by Apple
Link-room multicast Name resolution (LLMNR), by IETF

Search for services

Three solutions exist:

DNS Service Discovery (DNS-SD), protocol used by Apple
Service Hiring Protocol (SLP), described in the RFC 2608
Simple Service Discovery Protocol (SSDP) used in Universal Plug and Play (UPnP)

Allowance of IP addresses multicast

There does not exist standard.

Standard

The work group IETF Zeroconf led by Sun, Apple and Microsoft, published the RFC 3927.

Implementations

Apple Hello

Apple Hello (in the past Rendezvous) is an implementation of DNS-SD which exists under Mac OS X and Windows.

GNU/Linux

Many a distributions GNU/Linux integrates Zeroconf. The first implementations were based on Howl which had left the code provided by Apple. Then finally, an approach plus Linux was chosen by Freedesktop: avahi. This approach allows all to centralize and to limit the number of demons, the software wanting to use the services zeroconf makes their requests via Dbus.

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