that wish to register a domain name, even if they do not plan to establish an Internet connection in the immediate short term, should contact the administrator of the domain which most closely describes their activities.Even though the DNS supports many levels of sub-domains, delegations should only be made where there is a requirement for an organisation or organisational sub-division to manage their own name space. Any sub-domain administrator must also demonstrate they have the technical competence to operate a domain name server (described below), or arrange for another organisation to do so on their behalf.Domain Name ServersThe DNS is implemented as collection of inter-communicating nameservers. At any given level of the DNS hierarchy, a nameserver for a domain has knowledge of all the immediate sub-domains of that domain.For each domain there is a primary nameserver, which contains authoritative information regarding Internet entities within that domain. In addition Secondary nameservers can be configured, which periodically download authoritative data from the primary server. Secondary nameservers provide backup to the primary nameserver when it is not operational, and further improve the overall performance of the DNS, since the nameservers of a domain that respond to queries most quickly are used in preference to any others.4.17 /etc/resolv.confA) /etc/resolv.confWhen performing a name resolution most UNIX machines will check their /etc/hosts first and then check with their name server. How does the machine know where its domain name server is. The answer is in the /etc/resolv.conf file.resolv.conf is a text file with three main types of entries# commentsAnything after a # is a comment and ignored.domain nameDefines the default domain. This default domain will be appended to any hostname that does not contain a dot.nameserver addressThis defines the IP address of the machines domain name server. It is possible to have multipl...
