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DNS Settings

DNS settings determine which servers and services belong to a domain — for example, which website is loaded or where emails are delivered. A DNS zone file contains various record types, each serving a specific purpose.

Basic principle of DNS​

  • The Domain Name System, or DNS for short, translates human-readable domain names like example.com into IP addresses that servers on the internet can be reached at.
  • Each DNS record typically consists of a name (e.g. www), a type (e.g. A), content/value (e.g. an IP address), and a time-to-live value (TTL).
  • The complete set of records for a domain is called a DNS zone and is stored on the authoritative name servers of that domain.

Important basic records​

  • A record: Maps a hostname to an IPv4 address, e.g. "example.com → 1.2.3.4"
  • AAAA record: Same as an A record, but points to an IPv6 address, e.g. "example.com → 2001:db8::1"
  • CNAME record: Defines an alias, e.g. "blog.example.com → www.example.com", pointing to another hostname rather than directly to an IP. Changes to the IP addresses of the www.example.com entry are automatically propagated to the CNAME record in this example.
  • MX record: Specifies which mail servers accept emails for a domain, e.g. "example.com → mail.example.com", usually with a priority value (e.g. 10, 20 for backup servers).
  • TXT record: Carries freely definable text information, such as SPF, DKIM, or DMARC data for spam protection and email authentication. Can also be used to verify domain ownership.
  • SPF (as TXT type): Defines which servers are allowed to send emails on behalf of the domain; technically implemented as a special TXT record.

Infrastructure records​

  • NS record: Specifies which name servers are responsible for a zone, e.g. "example.com → ns1.example.com", and is required for other DNS servers to correctly resolve the domain.
  • SOA record: The "Start of Authority" record contains basic zone data, such as the primary name server address, admin email, and update intervals.
  • CAA record: Specifies which certificate authorities (CAs) are allowed to issue TLS/SSL certificates for a domain.
  • SRV record: Describes the host and port on which a specific service is available, e.g. for SIP, XMPP, or Microsoft services, including priority and weight.

Notes on settings​

  • Changes are usually made in the control panel of your domain provider, in the DNS or name server section, where new records can be created or existing ones updated.
  • After saving, it can take anywhere from a few minutes to 48 hours for new DNS entries to become visible globally due to caching and TTL settings.