What records a Premium DNS zone holds

A Premium DNS zone holds the same record types a DNS zone anywhere holds. If you already know what an MX record is, there is nothing new here — this page is the reference for what each field means and what the service accepts.

How a Premium DNS zone is edited

The Premium DNS interface is our provider's, and it has no address of its own and no separate sign-in: it opens only from inside their control panel, which is ours rather than yours.

So tell us what you need in the zone and we will set it — contact us with the records, or send them on a support ticket. The Manage DNS page in your account edits the free zone, which is a different zone from this one.

Every record has a TTL

Time To Live is how long, in seconds, other servers may keep a copy of the answer before asking again.

One day is the sensible default. It cannot be set below two minutes. Lower it a day or two before you plan to change a record, so the old answer expires quickly when the change lands — lowering it at the same time as the change does nothing, because the old TTL is the one already cached.

The record types

A — an IPv4 address

Points a name at a server. Your host gives you the address.

AAAA — an IPv6 address

The same thing for IPv6, which is a far larger address space: an IPv6 address is 128 bits where an IPv4 address is 32.

Your host gives you one or the other. An IPv4 address goes in an A record, an IPv6 address in an AAAA record; neither substitutes for the other.

CNAME — an alias

Makes one name an alias of another, so both reach the same place.

The usual use is www: an A record for yourdomain.com and a CNAME for www.yourdomain.com pointing at it, so the site answers with and without the prefix. It is also how a name is kept working while whatever is behind it is renamed.

MX — where email is delivered

Names the mail server that handles email for the domain. A sending server looks up the MX record first, then the address record for the server it names.

Priority only matters when there is more than one: delivery is attempted at the lowest number, then the next, and so on.

TXT — free text, and what it is really for

Holds up to 255 characters of text against a name. It carries no function of its own, which is exactly why other systems use it to publish policy:

• SPF — which servers are allowed to send mail using your domain. A receiving server reads it and can treat mail from anywhere else as forged.
• DKIM — the public half of the key your mail is signed with, so a recipient can tell the message was not altered in transit.
• DMARC — what a receiving server should do when SPF or DKIM fails, and where to report it.

Several TXT records are allowed on the same name. Their order is not preserved, so nothing may depend on it.

NS — delegation

Names the servers authoritative for a zone. Its real job is delegation: handing a subdomain to different nameservers.

If you delegate sub.yourdomain.com to a nameserver whose own name is inside that subdomain — ns1.sub.yourdomain.com — then an A record for that nameserver has to exist in the parent zone as well. Without it there is no way to find the server being delegated to. That extra record is called a glue record.

SRV — a service on a host and port

Says where a named service lives. Calendar sync, chat, VoIP and some mail clients look for one; you add it when a service's own instructions ask for it.

CAA — which authorities may issue certificates

Names the certificate authorities allowed to issue for the domain. Anyone else is expected to refuse.