1 DNS: is a standard technology for managing the names of Web sites and other Internet domains.
2 Domain: a domain is a sub network made up of a group of clients and servers under the control of one central security database. Within a domain, users authenticate once to a centralized server known as a domain controller, rather than repeatedly authenticating to individual servers and services. Individual servers and services accept the user based on the approval of the domain controller.
3 FQDN: is a domain name that specifies its exact location in the tree hierarchy of the Domain Name System (DNS). It specifies all domain levels, including the top-level domain and the root zone.
4 DNS Resolver: The client-side of the DNS is called a DNS resolver. It is responsible for initiating and sequencing the queries that ultimately lead to a full resolution (translation) of the resource sought, e.g., translation of a domain name into an IP address.
5 Host Name: is a label that is assigned to a device connected to a computer network and that is used to identify the device in various forms of electronic communication such as the World Wide Web, e-mail or Usenet. Hostnames may be simple names consisting of a single word or phrase, or they may be structured.
6 DNS Zone: is a portion of a domain name space using the Domain Name System (DNS) for which administrative responsibility has been delegated.
7 Zone File: zone file is a text file that describes a DNS zone. The zone file contains mappings between domain names and IP addresses and other resources, organized in the form of text representations of resource records (RR). A zone file may be either a DNS master file, authoritatively describing a zone, or it may be used to list the contents of a DNS cache.
8 DNS Iterative Query: it returns the IP address of the requested host name if it knows the address. If the server doesn’t know the address, it returns a referral, which is simply the address of a DNS server that should know.
9 DNS Recursive Query: the server must reply with either the IP address of the requested host name or an error message indicating that the host name doesn’t exist. If the server doesn’t have the information, it asks another DNS server for the IP address.
10 DNS Primary Server: translates host names and internet domains to IP addresses. It is a standard technology to manage website names and internet domains.
11 DNS Secondary Server: The secondary DNS acts as backup for the Primary DNS in case the Primary DNS does not work.
12 DNS caching-only server: Caching name servers, also called DNS caches, store DNS query results for a period of time determined in the configuration (time-to-live) of each domain-name record. DNS caches improve the efficiency of the DNS by reducing DNS traffic across the Internet, and by reducing load on authoritative name-servers, particularly root name-servers.
13 Resource Record: (RR) is the basic data element in the domain name system. Each record has a type (A, MX, etc.), an expiration time limit, a class, and some type-specific data.
14 /etc/named.conf file
15 Forward DNS lookup is using an Internet domain name to find an IP address.
16 Reverse DNS lookup is using an Internet IP address to find a domain name.
17 A Ipv4 Address Maps a Domain name to Ipv4 address fo a host.
18 CNAME Maps a alias or nickname to a domain name.
19 MX Specifies a destination for mail addressed to the domain.
20 NS Specifies a destination for mail addressed to the domain.
21 PTR Maps IP address to a domain name and is used for reverse name resolution.
22 SOA Designates the start of a zone.
23 IN
24 @
25 $TTL Sets the default Time to Live (TTL) value for the zone. This is the length of time, in seconds, that a zone resource record is valid. Each resource record can contain its own TTL value, which overrides this directive.
26 $ORIGIN Appends the domain name to unqualified records, such as those with the hostname and nothing more.
27 $INCLUDE Configures named to include another zone file in this zone file at the place where the directive appears. This allows additional zone settings to be stored apart from the main zone file.
28 allow-query { any } ; Defines the networks from which clients can post DNS requests.
29 listen-on port 53 Tells BIND on which network interfaces and port to accept client queries.
30 directory “/var/named” ; Specifies the directory in which BIND can find the files containing the zone data.
31The named.conf file defines the name server configuration and tells named where to obtain the name server database information. BIND 8 uses the following configuration commands: key, acl, options, logging, zone, server, controls, and trusted-keys. BIND 9 uses the same eight commands and adds the view command.
32.Looks for file names with bind
33 Runs service called named
34 stop services called named
