Each zone must be managed by using at least one primary and one secondary DNS name server. A primary name server contains the original name- to - IP address mappings in a zone file located on the local computer. A secondary name server contains a copy of the zone's name- to - IP address mappings. It receives this copy from a master name server, either the primary server or some other secondary DNS server.
Note
Although a secondary name server can receive its zone data from another secondary name server, this configuration is not recommended. It is recommended that a secondary name server receive the zone data from a primary zone server. For more information, see Request for Comments (RFC) 1912, "Common DNS Operational and Configuration Errors." RFCs are the official documents of the Internet Engineering Task Force (IETF) specifying the details for TCP/IP protocols.
Using both a primary and a secondary server is required to provide database redundancy and a degree of fault tolerance. Providing a primary and a secondary DNS name server is also a requirement for domain registration with InterNIC.
If you establish a site on the Internet and register your enterprise with InterNIC, you must provide information about both your primary and secondary name servers. InterNIC established this requirement to ensure registered domains can always provide the name- to - IP address mappings needed for Internet connectivity. For more information about primary and secondary DNS servers, see later sections of this chapter.
Note
For more information about InterNIC registration requirements, contact the InterNIC registration site at: http://www.internic.net/.