Domains, DNS and hosting, explained once

A nameserver is the directory that tells the internet where to send a request when someone types your domain into a browser. It does not hold your files: it holds a set of instructions, called DNS records, that say where those files and your email actually live. Change the nameserver and you change which set of instructions the internet reads; change a record within it and you change one specific instruction.

The A record points a name at a computer

An A record connects your domain name to the numerical address of the server that holds your website files, in the form of an IP address such as 192.0.2.1. This is the simplest and most common record: it answers the question 'where is this site actually stored'. If you move your files to a new host, this is usually the record that changes.

The CNAME record points a name at another name

A CNAME record does a similar job but points one name at another name, which is useful for things like www.yourname.co.uk pointing to yourname.co.uk, or a subdomain pointing at a service run by someone else entirely. It is an alias: the target still resolves through its own A record eventually.

The MX record decides where your email goes

An MX record (mail exchange) tells the internet which server handles email for your domain, and it is entirely separate from the record that serves your web pages. This is why a website can move host without a single email going missing, or why email can stop working after a rushed domain move while the site itself still loads fine. If your contact form sends enquiries to a named inbox, the MX record is what gets them there; see Enquiry forms and visitor data, done properly for what happens to that data once it arrives.

Other records you may meet

A few other record types turn up when you set up email or verify a service:

• TXT record: a plain text entry, often used to prove you own a domain or to authorise a service to send email on your behalf.
• SPF and DKIM: both stored as TXT records, they tell receiving mail servers that messages from your domain are genuine, which reduces the chance of your emails landing in spam.

Why a change does not take effect at once

When you edit a DNS record, that change has to spread across the many servers around the internet that cache the old answer, a process called propagation. It can take anywhere from a few minutes to around 48 hours, so a site or mailbox that still looks wrong an hour after a change is usually just waiting.

A UK domain name usually comes in one of two endings: .co.uk and .uk. Both are administered by Nominet, the organisation that runs the registry for UK domain names, and both mark a site out as based in the UK. The difference between them is partly historical and partly a matter of Nominet's own registration rules.

What Nominet's rules say

Nominet opened .uk for direct registration in 2014. Anyone who already held the matching .co.uk name, registered before 28 October 2013, was given first refusal on the shorter .uk version, a reservation period that ran until 30 June 2019. After that date, any .uk name left unclaimed became available to whoever registered it first, regardless of who held the matching .co.uk. There is no rule today requiring you to hold a .co.uk before registering a .uk, or the other way round: the two are registered and renewed independently of each other.

The practical difference

.co.uk has been the default ending for UK businesses since the 1990s, so it is the one most people type from memory and the one that reads as familiar on a business card or the side of a van. .uk is shorter and equally tied to the UK, but carries no long-standing convention, so a visitor seeing it for the first time has nothing to compare it against. Neither ending affects how a search engine ranks the site.

Which to register

If someone else already holds the matching .co.uk or .uk for your preferred name, that usually settles the question. Where both are free, our view is that .co.uk remains the safer default for a business or club that wants to look established, because it is the form most UK visitors already expect. A wedding page or a short-lived campaign page, where recognition built up over years does not matter, is a reasonable place to use .uk instead. Registering both, and pointing the one you do not use at the one you do, costs little and closes off the most common source of confusion: someone else taking the name you left free.

A domain registration runs for a fixed term, usually a year at a time, and renewing it before that term ends is the only thing that keeps the name yours. Miss the renewal and the domain does not vanish instantly, but it does move through a sequence of stages that gets harder to reverse at each step, and the further along that sequence you are, the more it costs and the less certain the outcome.

The stages between expiry and loss

When a domain passes its renewal date without payment, most registrars (the companies that hold domain names on their customers' behalf) allow a short window where the domain still resolves and can usually be renewed at the normal price. After that, the domain is typically suspended: the website and any email tied to it stop working, though the registration itself has not yet been given up. A further period follows where the domain can often still be recovered, but usually only at a higher fee and sometimes only by contacting the registrar directly. Once that recovery window closes, the domain is released and becomes available for anyone to register, including someone with no connection to the original owner.

For .uk domains specifically, the registry is run by Nominet, and it is Nominet's own policy, not the registrar's, that ultimately governs how long a lapsed .uk domain can be recovered and on what terms. Registrars vary in how they present this to customers, so the safest source is Nominet's own published guidance on domain expiry and recovery, checked directly.

Getting a lapsed domain back

A domain in the recovery stage is not gone, but it is no longer routine to reclaim. Expect to deal with the registrar or registry directly, expect a higher fee, and expect the process to take longer.

• Confirm which stage the domain is in: still renewable, suspended, or in the recovery period
• Contact the registrar that held the domain, since recovery is rarely available through a normal purchase flow
• Move quickly once the domain is in the recovery period, because the window is time limited and closes into public release

What to check now, before it becomes a problem

The practical fix is almost entirely about not reaching this stage in the first place. A wedding photographer who registers a domain to match a single busy season, then forgets it exists once the bookings stop, is a common way these lapses happen, and the domain is often only noticed once a client tries to reach a site that no longer loads.

• Set the domain to renew automatically wherever the registrar offers it
• Keep the payment card and contact email on the domain account current, since renewal failures usually come from an expired card or a bounced notice
• Check renewal reminder emails against a spam folder at least once, since these notices are routinely filtered out

Once the domain itself is secure, the next question is what the site sitting on it is legally required to show: see What a UK Website Must Show by Law. And for the practical steps around going live and keeping the whole thing running afterwards, see The Launch Checklist and the First Month.