The document discusses the Domain Name System (DNS) and how it works. DNS is an internet directory service that maps hostnames to IP addresses, allowing users to use names instead of numbers. It uses a distributed, hierarchical system of name servers to perform this name resolution in a scalable way. DNS caches mappings for performance, starting queries at the highest level domains and following delegations between servers until the answer is found. DNS has become a major attack vector, so protection of DNS infrastructure and traffic is important.
Domain Name System (DNS) is a hierarchical naming system that maps domain names to IP addresses. DNS maintains the domain namespace and provides translation between domain names and IP addresses using DNS name servers and a communication protocol. DNS refers to the data query service, system of mapping names to IP addresses hierarchically, and DNS servers that translate host names to IP addresses. Before DNS was invented, host name to IP address mappings were stored in a file. DNS was developed in the 1980s and the dominant DNS software, BIND, was introduced. Security vulnerabilities include cache poisoning, client flooding, and dynamic update vulnerabilities. Efforts are made to improve DNS security.
The DNS name resolution process involves a DNS server checking its local cache, hosts file, and forwarding the request to higher-level DNS servers if the address is not found. As a last resort, the root hints file is used to forward the request to a root DNS server, which will then direct the request to a top-level domain server that can provide the IP address. DNS translates hostnames to IP addresses through a hierarchical system of root, top-level, and authoritative DNS servers.
Overview of the Domain Name System (DNS). In the early days of the Internet, hosts had a fixed IP address. Reaching a host required to know its numeric IP address. With the growing number of hosts this scheme became quickly awkward and difficult to use. DNS was introduced to give hosts human readable names that would be translated into a numeric IP addresses on the fly when a requesting host tried to reach another host. To facilitate a distributed administration of the domain names, a hierarchic scheme was introduced where responsibility to manage domain names is delegated to organizations which can further delegate management of sub-domains. Due to its importance in the operation of the Internet, domain name servers are usually operated redundantly. The databases of both servers are periodically synchronized.
The document discusses the Domain Name System (DNS) and its components. It explains what DNS is, how it works to translate domain names to IP addresses, the different record types used in DNS like A, NS, MX records. It describes DNS name servers, resolvers, zones and namespaces. It provides examples of DNS configuration files for both master and slave name servers as well as sample zone files mapping names to IP addresses.
The document discusses the Domain Name System (DNS). It describes DNS as a hierarchical and distributed database that maps hostnames to IP addresses. DNS uses a tree structure with nodes containing domain names that are read from the node up to the root. The document outlines the key components of DNS including fully and partially qualified domain names, zones, primary and secondary name servers, and the different top-level domains like generic, country, and inverse domains used for name to address and address to name lookups.
The document discusses the Domain Name System (DNS), which translates domain names to IP addresses and vice versa. It describes the hierarchical structure of DNS with zones, resource records, and name servers. Primary and secondary name servers maintain authoritative data for zones, while caching name servers store previously looked up data to improve performance. The domain name resolution process involves queries to authoritative and caching name servers to map names to addresses.
The Domain Name System (DNS) is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. A domain name represents an Internet Protocol (IP) resource ultimately identifiable by a numeric IP address. DNS servers store records that map domain names to IP addresses and vice versa. The DNS hierarchy consists of root name servers at the top, authoritative name servers for top-level domains and their subdomains below them. When a user enters a domain name, the DNS server first checks its cache and if it doesn't find a match, it queries authoritative name servers to resolve the IP address associated with the domain name.
The document discusses the Domain Name System (DNS) which maps domain names to IP addresses. DNS uses a client-server model where clients (resolvers) query name servers to lookup addresses. It describes the hierarchical namespace structure and how names are organized into domains with labels separated by dots. Resource records containing domain, type, class and data are stored in distributed databases to map names and addresses. Caching improves performance by storing recent lookups.