the domain name system - itu.ppt

Copyright ? 2001, Nominum, ENUM WorkshopJan 17, 2000A Quick Introduction to the Domain Name SystemDavid Conrad<@>Chief Technology OfficerCopyright ? 2001, Nominum, ENUM WorkshopJan 17, 2000Overview?Introduction to the DNS?ponents?DNS Structure and Hierarchy?The DNS in ContextCopyright ? 2001, Nominum, ENUM WorkshopJan 17, 2000The DNS is…?The “Domain Name System”–Created in 1983 by Paul Mockapetris (RFCs1034 and 1035), modified, updated, and enhanced by a myriad of subsequent RFCs?What users use to reference anything by name on the ?The mechanism by which software translates names to addresses and vice versaCopyright ? 2001, Nominum, ENUM WorkshopJan 17, 2000A Quick Digression:Names versus Addresses?An address is how you get to an endpoint–Typically, hierarchical (for scaling):?950 Charter Street, Redwood City CA, 94063?, +1-650-381-6003?A “name” is how an endpoint is referenced–Typically, no structurally significant hierarchy?“David”, “Tokyo”, “”Copyright ? 2001, Nominum, ENUM WorkshopJan 17, 2000The DNS is also…?A lookup mechanism for translating objects into other objects?A globally distributed, loosely coherent, scalable, reliable, dynamic prised of ponents–A “name space”–Servers making that name space available–Resolvers (clients) which query the servers about the name spaceCopyright ? 2001, Nominum, ENUM WorkshopJan 17, 2000DNS as a Lookup Mechanism?Users generally prefer names to puters prefer numbers to names?DNS provides the mapping between the two–I have “x”, give me “y”?DNS is NOT a directory service–No way to search the database?No easy way to add this functionalityCopyright ? 2001, Nominum, ENUM WorkshopJan 17, 2000DNS as a Database?Keys to the database are “domain names”–, -, ?Over 100,000,000 domain names stored?Each domain name contains one or more attributes–Known as “resource records”?Each attribute individually retrievableCopyright