Domain name system

lists mail exchange servers accepting e-mail for each domain. In providing a worldwide keyword-based redirection service, DNS is an essential component of contemporary Internet use.

DNS is useful for several reasons. Most well known, the DNS makes it possible to attach easy-to-remember domain names (such as "checkdns.net") to hard-to-remember IP addresses (such as 195.60.98.252). Humans take advantage of this when they recite URLs and e-mail addresses. Less recognized, the domain name system makes it possible for people to assign authoritative names, without needing to communicate with a central registrar each time.

Contents 1 A brief history of the DNS 2 How the DNS works in theory 2.1 Understanding the parts of a domain name 2.2 An example of theoretical DNS recursion 2.3 Understanding domain registration and glue records 3 DNS in practice 3.1 Caching and time to live 3.2 Caching time 3.3 DNS in the real world 3.3.1 Broken resolvers 3.4 Other DNS applications 4 Standards 5 Types of DNS records 6 Internationalized domain names 7 Legal users of domains 7.1 Registrant 7.2 Administrative contact 7.3 Technical contact 7.4 Billing contact 7.5 Name servers 8 Politics 8.1 Truth in Domain Names Act 9 DNS How To... (Microsoft TechNet) Install and Configure Servers Install and Configure Clients Manage Servers Optimize Servers Monitor Servers Add and Remove Zones Manage Zones Manage Resource Records Use Aging and Scavenging 10 Checklists Checklist: Installing a DNS server Checklist: Configuring a DNS server Checklist: Deploying DNS Checklist: Deploying DNS for Active Directory Checklist: Verifying DNS before installing Active Directory Checklist: Securing your DNS infrastructure 11 DNS best practices 12 Troubleshooting Troubleshooting DNS clients Troubleshooting DNS servers Troubleshooting dynamic updates Troubleshooting zone problems 13 References links