EDNS Client Subnet Check

An open IETF standard edns-client-subnet was developed in order to better direct content to users and lower latency in cooperation between recursive DNS services and CDN providers. For example, when using Open DNS or Google Public DNS, and you visit a website served from a CDN provider which supports EDNS client subnet, like KeyCDN, a truncated version of your IP is added to the DNS request, which then routes the client based on the geo location of the client subnet to the most optimal server.

What is a DNS?

DNS, which stands for domain name system, is an Internet service that translates domains names into IP addresses. This query is performed by a Domain Name Server (DNS server) or servers nearby that have been assigned responsibility for that hostname. You can think of a DNS server as a phone book for the internet. A DNS server maintains a directory of domain names and translates them to IPs.

Common DNS Records

• A: Indicates the IP address of the domain.
• AAAA: IPV6 address record.
• CNAME: Canonical name, used for making a domain alias.
• NS: Name server, indicates which name server is authoritative for the domain.
• MX: Mail exchange, a list of mail exchange servers used for the domain.
• TXT: Administrator record use for domain facts and verifications.
• SRV: Service, defines the TCP service the domain operates on.
• PTR: Pointer record, maps an IPv4 address to CNAME.
• SOA: State of authority, stores information about when domain was updated.