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Glossary of website and domain terms

Short definitions of the terms you meet in this Help Center. Each one links to a guide that explains it in more depth where one exists.

A to C​

  • A record: A DNS record that points a name to an IPv4 address, such as 203.0.113.10. See DNS records explained.
  • AAAA record: Like an A record, but for an IPv6 address, such as 2001:db8::10.
  • Apex domain: The domain itself, without any subdomain: example.com rather than www.example.com. Also called the root or bare domain. Many DNS editors write it as @.
  • Authorization code: A password-like code, sometimes called an EPP code or transfer code, that the current registrar gives you so another registrar can transfer the domain. Keep it private.
  • CAA record: A DNS record that lists which certificate authorities may issue SSL certificates for your domain.
  • Certificate authority (CA): An organization trusted by browsers to check who controls a domain and issue SSL certificates for it.
  • CNAME record: A DNS record that makes one name an alias of another name, for example www.example.com as an alias of example.com.
  • Control panel: The web dashboard where you manage a hosting account: files, databases, email accounts and settings.

D to H​

  • DKIM: DomainKeys Identified Mail. A digital signature added to outgoing email so receivers can check it really came from your domain and was not changed. See SPF, DKIM and DMARC.
  • DMARC: A DNS policy that tells receiving servers what to do with email that fails SPF and DKIM checks, and where to send reports.
  • DNS: The Domain Name System, which turns names such as example.com into the addresses computers use.
  • DNS zone: The full set of DNS records for one domain.
  • Domain lock: A setting at the registry that blocks transfers to another registrar until you remove it. Also called a transfer lock or registrar lock.
  • HTTPS: The secure version of HTTP, the protocol browsers use to load web pages. It encrypts the connection using an SSL/TLS certificate.

I to N​

  • IMAP: The protocol email apps use to read mail stored on the server, keeping every device in sync.
  • IP address: The numeric address of a device on the internet. IPv4 addresses look like 198.51.100.7; IPv6 addresses look like 2001:db8::7.
  • MX record: A DNS record that names the servers that receive email for your domain, each with a priority number.
  • Nameservers: The servers that hold your domain's DNS records and answer questions about them. Changing nameservers moves your whole DNS to another provider.

P to S​

  • Propagation: The time it takes for a DNS change to be seen everywhere, because networks keep copies of old answers until they expire. See Why DNS changes take time.
  • Registrar: A company accredited to register domain names on your behalf with the registries.
  • Registry: The organization that runs a top-level domain, such as .com or .org, and keeps the master list of names registered in it.
  • Root access: Full administrator control of a server's operating system. Common on a VPS or cloud server; not available on shared hosting.
  • SMTP: The protocol used to send email, both from your email app to your provider and between email servers.
  • SPF: Sender Policy Framework. A TXT record that lists the servers allowed to send email for your domain.
  • SSL certificate: A file installed on a web server that proves the website's identity and lets browsers encrypt the connection. The technology is now called TLS, but "SSL" is still the common name. See SSL certificates explained.
  • Subdomain: A name in front of your domain, such as shop.example.com, created in your DNS at no extra registration cost.

T to W​

  • TLD: Top-level domain: the extension at the end of a domain, such as .com, .net or .io.
  • TTL: Time to live. How long, in seconds, other networks may keep a copy of a DNS record before checking again. 3600 means one hour.
  • TXT record: A DNS record that holds text, used for SPF, DKIM, DMARC and ownership checks.
  • VPS: Virtual private server: a virtual machine with its own reserved resources and operating system. See Web hosting, VPS or cloud server?
  • WHOIS: A public lookup service for domain registration details. Many registrars, including DomainPilot, offer privacy protection that hides your personal contact details from it. Its modern replacement is called RDAP.

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