Web servers differentiate between hosted sites using different domain names – eg, is .au.A new organisation will need a domain registered for their network if they intend to connect to the Internet.create pointers to – authoritative server.ensure appropriate allocation – Identify organisations and responsible persons (not always done!).Caching-only – get answers for all name service queries from other name servers – non-authoritative use second-hand and incomplete DNS data.Secondary – periodically transfers from primary server - authoritative for their own domain.Loads information from disk has complete information about the domain always accurate Authoritative - only one server per domain Name Server software - Types BIND usually runs as the process “named” on systems that provide name service Categories of name server:
Consists of two parts: – resolver implements a policy that requests the lookup of a name – nameserver responds to the request.Name Server software DNS on UNIX systems use Berkeley Internet Name Daemon (BIND) Top-level servers have information about their particular domain eg… “org.au” server has all registered names listed.these have only information about top-level domains – au.Local servers cache responses for future useĭomain Hierarchy Top-level domain (.) has root servers.Consists of local network-based servers that connect to authoritative servers if they cannot resolve name.Provides distributed database of names and associated IP addresses.If unsatisfied, need to find a nameserver – use /etc/nf to search find resolver >.IP addresses & Names DNS, BOOTP, DHCP, IP Routing, Routing protocols
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