Computer Networks And The Domain Name System Information Technology Essay

Computer Networks And The Domain Name System Information Technology Essay Also popularly known as DNS which is the abbreviation for Domain Name System is a hierarchical naming system and an internet service that translates domain names into IP addresses. Alphabetic nature to these domain names makes us easier to understand while IP address with numbers and points can be difficult to remember. But Ultimately IP address is needed on the internet, therefore the DNS service translates the domain name into the corresponding IP address every time we use the domain names. Example: If the Domain name is www.example.com It contains the domain name example.com It might translate to:- 198.105.232.4 The emails address also carries the domain name such [emailprotected] How important is Domain Name Server to the Internet? It wont be wrong if we say that Internet would shut down very quickly without DNS, it is by far the largest, most active and efficient distributed databases in the planet. Domain name servers, or DNS, are an incredibly important but completely hidden part of the internet. If we spent any time of internet surfing, sending mails we are actually using domain name servers without even realizing it. Importance of DNS: The Domain Name System was Created in 1983 by Paul Mockapetris . It is the domain name system through which the World Wide Web, hyperlinks and internet contact information remain consistent and constant even if the arrangement of internet routing changes or the person uses another device such as mobile. People take advantage of this technique when they use meaningful Uniform Resource Locators (URLs) and e-mail addresses without having to know how the computer actually locates them/translates them, making it a hidden feature on the internet. DNS Server: Domain Name Server is a server that stores the DNS records, such as:- address (A) records, name server (NS) records, mail exchanger (MX) records for a domain name And then responds with answers to queries against its database. The Mechanism! The Domain Name System is basic requirement for the internet as it provides a worldwide, distributed keyword-based redirection service. The Domain Name System also stores other types of information, such as the list of mail servers that accept email for a given Internet domain. Domain Name System distributes the responsibility of assigning domain names and mapping those names to IP addresses by designating authoritative name servers for each domain. Authoritative name servers are assigned to be responsible for their particular domains, and in turn can assign other authoritative name servers for their sub-domains. This mechanism has made the DNS distributed and fault tolerant and has helped avoid the need for a single central register to be continually consulted and updated. The Domain Name System also defines the technical underpinnings of the functionality of this database service. For this purpose it defines the DNS protocol, a detailed specification of the data structures and communication exchanges used in DNS, as part of the Internet Protocol Suite. Domain Name Formulation: Domain name is divided into one or more parts, which is technically called labels that are conventionally concatenated, and delimited by dots, such as example.com The right most labels tell us the top-level domain like in www.example.com belongs to the top level domain com. The hierarchy of domains descends from right to left; each label to the left specifies a subdivision, or subdomain of the domain to the right. For example: the label example specifies a subdomain of the com domain, and www is a sub domain of example.com. This tree of subdivisions may consist of 127 levels. Each label may contain up to 63 characters. The full domain name may not exceed a total length of 253 characters. In practice, some domain registries may have shorter limits. DNS names may technically consist of any character representable in an octet. The characters allowed in a label are a subset of the ASCII character set, and includes the characters a through z, A through Z, digits 0 through 9, and the hyphen. This rule is known as the LDH rule (letters, digits, hyphen). Domain names are interpreted in case-independent manner. Labels may not start or end with a hyphen . A hostname is a domain name that has at least one IP address associated. For example, the domain names www.example.com and example.com are also hostnames, whereas the com domain is not. Operations: Before understanding the Operation first we should know what is DNS Resolver, it is the client-side of a DNS. 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. Now lets focus on the Operation which uses the address resolution mechanism in which Domain name resolvers determine the appropriate domain name servers responsible for the domain name in question by a sequence of queries starting with the right-most (top-level) domain label. The process entails: 1. A system that needs to use the DNS is configured with the known addresses of the root servers. This is often stored in a file of root hints, which are updated periodically by an administrator from a reliable source. 2. Query one of the root servers to find the server authoritative for the top-level domain. 3. Query the obtained TLD DNS server for the address of a DNS server authoritative for the second-level domain. 4. Repeating the previous step to process each domain name label in sequence, until the final step which would, rather than generating the address of the next DNS server, return the IP address of the host sought. Protocol details: DNS primarily uses User Datagram Protocol (UDP) on port number 53 to serve requests. DNS queries consist of a single UDP request from the client followed by a single UDP reply from the server. TCP protocol which stands for Transmission Control Protocol is used when the response data size exceeds 512 bytes, or for tasks such as zone transfers. Conclusion: Doing the Research for this term report I was able to know about the DNS which is essential part of the internet functionality but is hidden from us, it has made our life easier as we dont need to remember the IP address and we just have to recite the alphabetical name and DNS itself translates it to the IP address. This Mechanism has surely made things more easier and efficient.