The\u00c2\u00a0Domain Name System\u00c2\u00a0(DNS) is a\u00c2\u00a0hierarchical\u00c2\u00a0and\u00c2\u00a0decentralized\u00c2\u00a0naming system for computers, services, or other resources connected to the\u00c2\u00a0Internet\u00c2\u00a0or a private network. It associates various information with\u00c2\u00a0domain names\u00c2\u00a0assigned to each of the participating entities. Most prominently, it translates more readily memorized domain names to the numerical\u00c2\u00a0IP addresses\u00c2\u00a0needed for locating and identifying computer services and devices with the underlying\u00c2\u00a0network protocols. By providing a worldwide,\u00c2\u00a0distributed\u00c2\u00a0directory service, the Domain Name System has been an essential component of the functionality of the Internet since 1985.<\/p>\n
The Domain Name System delegates the responsibility of assigning domain names and mapping those names to Internet resources by designating\u00c2\u00a0authoritative name servers\u00c2\u00a0for each domain. Network administrators may delegate authority over\u00c2\u00a0sub-domains\u00c2\u00a0of their allocated name space to other name servers. This mechanism provides distributed and\u00c2\u00a0fault-tolerant\u00c2\u00a0service and was designed to avoid a single large central database.<\/p>\n
The Domain Name System also specifies the technical functionality of the\u00c2\u00a0database\u00c2\u00a0service that is at its core. It defines the DNS protocol, a detailed specification of the data structures and data communication exchanges used in the DNS, as part of the\u00c2\u00a0Internet Protocol Suite.<\/p>\n
The Internet maintains two principal\u00c2\u00a0namespaces, the domain name hierarchy\u00c2\u00a0and the\u00c2\u00a0Internet Protocol\u00c2\u00a0(IP)\u00c2\u00a0address spaces.\u00c2\u00a0The Domain Name System maintains the domain name hierarchy and provides translation services between it and the address spaces. Internet\u00c2\u00a0name servers\u00c2\u00a0and a\u00c2\u00a0communication protocol\u00c2\u00a0implement the Domain Name System.\u00c2\u00a0A DNS name server is a server that stores the DNS records for a domain; a DNS name server responds with answers to queries against its database.<\/p>\n
The most common types of records stored in the DNS database are for Start of Authority (SOA),\u00c2\u00a0IP addresses\u00c2\u00a0(A\u00c2\u00a0and\u00c2\u00a0AAAA),\u00c2\u00a0SMTP\u00c2\u00a0mail exchangers\u00c2\u00a0(MX), name servers (NS), pointers for\u00c2\u00a0reverse DNS lookups\u00c2\u00a0(PTR), and\u00c2\u00a0domain name aliases\u00c2\u00a0(CNAME). Although not intended to be a general purpose database, DNS has been expanded over time to store records for other types of data for either automatic lookups, such as\u00c2\u00a0DNSSEC\u00c2\u00a0records, or for human queries such as\u00c2\u00a0responsible person\u00c2\u00a0(RP) records. As a general purpose database, the DNS has also been used in combating\u00c2\u00a0unsolicited email\u00c2\u00a0(spam) by storing a\u00c2\u00a0real-time blackhole list\u00c2\u00a0(RBL). The DNS database is traditionally stored in a structured text file, the\u00c2\u00a0zone file, but other database systems are common.<\/p>\n
An often-used analogy to explain the Domain Name System is that it serves as the\u00c2\u00a0phone book\u00c2\u00a0for the Internet by translating human-friendly computer\u00c2\u00a0host-names\u00c2\u00a0into IP addresses. For example, the domain name\u00c2\u00a0www.example.com\u00c2\u00a0translates to the addresses\u00c2\u00a093.184.216.34<\/span><\/i>\u00c2\u00a0(IPv4) and\u00c2\u00a02606:2800:220:1:248:1893:25c8:1946<\/span><\/i>\u00c2\u00a0(IPv6). The DNS can be quickly and transparently updated, allowing a service’s location on the network to change without affecting the end users, who continue to use the same host-name. Users take advantage of this when they use meaningful Uniform Resource Locators (URLs) and\u00c2\u00a0e-mail addresses\u00c2\u00a0without having to know how the computer actually locates the services.<\/p>\n An important and ubiquitous function of DNS is its central role in distributed Internet services such as\u00c2\u00a0cloud services\u00c2\u00a0and\u00c2\u00a0content delivery networks.\u00c2\u00a0When a user accesses a distributed Internet service using a URL, the domain name of the URL is translated to the IP address of a server that is proximal to the user. The key functionality of DNS exploited here is that different users can\u00c2\u00a0simultaneously\u00c2\u00a0receive different translations for the\u00c2\u00a0same\u00c2\u00a0domain name, a key point of divergence from a traditional phone-book view of the DNS. This process of using the DNS to assign proximal servers to users is key to providing faster and more reliable responses on the Internet and is widely used by most major Internet services.<\/p>\n The DNS reflects the structure of administrative responsibility in the Internet.\u00c2\u00a0Each subdomain is a\u00c2\u00a0zone\u00c2\u00a0of administrative autonomy delegated to a manager. For zones operated by a\u00c2\u00a0registry, administrative information is often complemented by the registry’s\u00c2\u00a0RDAP\u00c2\u00a0and\u00c2\u00a0WHOIS\u00c2\u00a0services. That data can be used to gain insight on, and track responsibility for, a given host on the Internet.<\/p>\n DNS primarily uses the\u00c2\u00a0User Datagram Protocol\u00c2\u00a0(UDP) on\u00c2\u00a0port number\u00c2\u00a053 to serve requests.\u00c2\u00a0DNS queries consist of a single UDP request from the client followed by a single UDP reply from the server. When the length of the answer exceeds 512 bytes and both client and server support\u00c2\u00a0EDNS, larger UDP packets are used. Otherwise, the query is sent again using the\u00c2\u00a0Transmission Control Protocol\u00c2\u00a0(TCP). TCP is also used for tasks such as\u00c2\u00a0zone transfers. Some resolver implementations use TCP for all queries.<\/p>\n The above is a brief about Domain Name System. Watch this space for more updates in the latest trends in Technology.<\/p>\n","protected":false},"excerpt":{"rendered":" The\u00c2\u00a0Domain Name System\u00c2\u00a0(DNS) is a\u00c2\u00a0hierarchical\u00c2\u00a0and\u00c2\u00a0decentralized\u00c2\u00a0naming<\/p>\n","protected":false},"author":1,"featured_media":1435,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[443,7],"tags":[444,18],"class_list":["post-1434","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-domain-name-system","category-techtrends","tag-domain-name-system","tag-technology"],"_links":{"self":[{"href":"https:\/\/blog.amt.in\/index.php\/wp-json\/wp\/v2\/posts\/1434","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.amt.in\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.amt.in\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.amt.in\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.amt.in\/index.php\/wp-json\/wp\/v2\/comments?post=1434"}],"version-history":[{"count":1,"href":"https:\/\/blog.amt.in\/index.php\/wp-json\/wp\/v2\/posts\/1434\/revisions"}],"predecessor-version":[{"id":1436,"href":"https:\/\/blog.amt.in\/index.php\/wp-json\/wp\/v2\/posts\/1434\/revisions\/1436"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blog.amt.in\/index.php\/wp-json\/wp\/v2\/media\/1435"}],"wp:attachment":[{"href":"https:\/\/blog.amt.in\/index.php\/wp-json\/wp\/v2\/media?parent=1434"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.amt.in\/index.php\/wp-json\/wp\/v2\/categories?post=1434"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.amt.in\/index.php\/wp-json\/wp\/v2\/tags?post=1434"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}