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Posts Tagged ‘LLMNR’

Automatic hosts name resolution technics

January 19, 2011 Leave a comment

In this post, you will discover some well known hosts name resolution technics in a LAN. The purpose is to resolve hosts names without any manual configuration or using a third party solution. This feature is proposed by the zeroconf paradigm.

  • LLMNR (Link Local Multicast Name Resolution): Recently, Microsoft has developed this protocol and integrated it into Windows 2008/2008R2 and Windows Vista/7. The principle is to send multicast (not broadcast) name resolution requests to some machines (which have Networking Discovery feature activated). ¬†This protocol is based on IPv6 but it can ¬†theoretically use IPv4 and send requests to the 224.0.0.252 address.
  • mDNS (Multicast DNS): this protocol is proposed by Apple and aims to provide an automatic name resolution through a decentralized DNS . Each host host its special DNS table with the classical records. With mDNS, a host has the ability to choose any DNS suffix and and announce its new name through a multicast address. The name resolution requests are sent to ¬†224.0.0.251 for IPv4 and ff02::fb for IPv6. mDNS is more used than LLMNR for its compatibility with DNS-SD (DNS based Service Discovery); another Apple product; which aims to facilitate Service Discovery and Announcement. Each host providing services advertises through DNS messages the different information. UPnP is another Microsoft solution but not so wellknown as DNS-SD which is supported by many hardware solutions, some linux distributions and so on.
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