Editing Zero-configuration networking (section)

===Link-local IPv4 addresses===
Where no DHCP server is available to assign a host an IP address, the host can select its own [[link-local address]]. Using a link-local address, hosts can communicate over this link but only locally; Access to other networks and the Internet is not possible. There are some link-local IPv4 address implementations available:
* Apple Mac OS and MS Windows have supported link-local addresses since [[Windows 98]] and [[Mac OS 8.5]] (both released in 1998).<ref name="rfc3927" /> Apple released its open-source implementation in the [[Darwin (operating system)|Darwin]] bootp package.
* [[Avahi (software)|Avahi]] contains an implementation of IPv4LL in the avahi-autoipd tool.
* Zero-Conf IP (zcip)<ref>{{Citation | url = http://zeroconf.sourceforge.net/ | title = zcip | publisher = Source forge}}</ref>
* [[BusyBox]] can embed a simple IPv4LL implementation.
* Stablebox,<ref>{{Citation | url = http://code.google.com/p/stablebox/ | title = Code | contribution = Stable box}}</ref> a fork from Busybox, offers a slightly modified IPv4LL implementation named llad.
* Zeroconf<ref>{{Citation | url = http://www.progsoc.uts.edu.au/~wildfire/zeroconf/ | title = Zeroconf | publisher = UTS | place = [[Australia|AU]] | access-date = 2005-05-04 | archive-url = https://web.archive.org/web/20050509093846/http://www.progsoc.uts.edu.au/~wildfire/zeroconf/ | archive-date = 2005-05-09 | url-status = dead }}</ref> is a package based on Simple IPv4LL, a shorter implementation by [[Arthur van Hoff]].<ref>{{Citation | url = http://www.zeroconf.org/AVH-IPv4LL.c | publisher = Zero conf | title = AVH IPv4LL | type = C source code}}</ref>

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.<ref>{{Citation | url = http://udhcp.busybox.net/lists/udhcp/2005-May/000124.html | publisher = Busy box | title = udhcpc | contribution = Zeroconf in udhcpc | type = electronic mail message | date = May 2005 | access-date = 2006-03-15 | archive-url = https://web.archive.org/web/20060206072249/http://udhcp.busybox.net/lists/udhcp/2005-May/000124.html | archive-date = 2006-02-06 | url-status = dead }}</ref>
* dhcpcd<ref>{{Citation | url = http://roy.marples.name/projects/dhcpcd/wiki | title = dhcpcd | first = Roy | last = Marples | type = project | format = wiki | access-date = 2011-01-07 | archive-url = https://web.archive.org/web/20100712131058/http://roy.marples.name/projects/dhcpcd/wiki | archive-date = 2010-07-12 | url-status = dead }}</ref> is an [[Open-source software|open source]] [[DHCP]] client for [[Linux]] and [[BSD]] that includes IPv4LL support.  It is included as standard in [[NetBSD]].

Neither of these implementations addresses kernel issues like broadcasting [[Address Resolution Protocol|ARP]] replies<ref>{{Citation | url = http://www.science.uva.nl/research/air/wiki/LinkLocalARPMeasurements | title = AIR | type = wiki | contribution = Link-Local ARP Measurements | publisher = UVA | place = [[Netherlands|NE]]}}</ref> or closing existing network connections.