The Internet’s system for converting alphabetic names into numeric IP addresses. For example, when a URL address is typed into a web browser, DNS servers return the IP address of the Web server associated with that name.

DNS plays a critical part in enabling email authentication systems. In some cases the information about which servers or networks are allowed to send email using a particular domain name is found in DNS. In other cases cryptographic keys used to verify the origin or contents of a message are found in DNS. Details are available in the descriptions of particular authentication systems, but without DNS or something like it, email itself – let alone email authentication – would be much more cumbersome.

The Internet’s system for converting alphabetic names into numeric IP addresses. For example, when a URL address is typed into a web browser, DNS servers return the IP address of the Web server associated with that name.

DNS plays a critical part in enabling email authentication systems. In some cases the information about which servers or networks are allowed to send email using a particular domain name is found in DNS. In other cases cryptographic keys used to verify the origin or contents of a message are found in DNS. Details are available in the descriptions of particular authentication systems, but without DNS or something like it, email itself – let alone email authentication – would be much more cumbersome.