Key facts
- £45 an hour + VAT for set-up
- No extra domain registration needed for subdomains
- A record for your own server, CNAME for hosted services
- Third-party verification TXT added where asked
- Delegation with NS records when another provider must control a subdomain
- Each subdomain needs its own SSL certificate coverage
What a subdomain is for
Your main domain, say yourdomain.co.uk, already covers every name in front of it. You do not need to register anything extra to use shop.yourdomain.co.uk, book.yourdomain.co.uk or portal.yourdomain.co.uk. Each one is just a DNS record in your existing zone.
Businesses use subdomains to keep a separate system under their own brand: an online shop on a hosted platform, a client portal, a help centre, an appointment booking tool, or a staging copy of the website for testing changes. www itself is a subdomain too.
Which record each job needs
| Use | Typical record |
|---|---|
| Points at your own server | A (IPv4) and, where available, AAAA (IPv6) |
| Hosted service such as a shop or help desk | CNAME to the hostname the provider gives you |
| Another company must run all DNS for it | NS records delegating the subdomain to their nameservers |
| Sending email from it | SPF, DKIM and, if it receives mail, MX |
A CNAME cannot share a name with any other record, so a subdomain that is a CNAME cannot also hold an MX or TXT record. We check this before choosing the record type.
Third-party platforms and verification
Most hosted platforms ask for two things: a CNAME pointing your chosen subdomain at their system, and a TXT record proving you own the domain. Some also ask for DKIM records so mail sent from the platform passes authentication. We add all of them, wait for the platform to confirm, then check the subdomain loads securely.
If your DNS is in Cloudflare, we decide whether the subdomain should be proxied or DNS only. Some platforms issue their own certificate and need DNS only to complete it.
SSL, staging and tidying up
- Certificates: a certificate for
yourdomain.co.ukdoes not automatically covershop.yourdomain.co.uk. The platform or server serving the subdomain must have a certificate for that name. A CAA record, if you have one, must allow the authority it uses. - Staging sites: we can point a
stagingsubdomain at a test copy so your developer can work without touching the live site. - Old subdomains: a CNAME left pointing at a service you have cancelled can sometimes be claimed by someone else on that platform. We remove records for services you no longer use.
www, wildcards and the root
The www name is usually a CNAME to the root domain or an A record to the same server. Either works; what matters is that both versions load and one redirects to the other, so visitors and search engines see a single address.
A wildcard record, written as *.yourdomain.co.uk, answers for any subdomain that has no record of its own. Some platforms ask for one, but it can hide typing mistakes and send stray names to your website. We only add a wildcard when a service genuinely needs it. Names with their own records are not affected by the wildcard.
How dijitul helps
Subdomain set-up is £45 an hour + VAT. Send us the details the platform gave you and we add the records, confirm verification and test the result. If you also want the subdomain to carry its own website, our sister team at dijitulwebdesign builds websites.
See DNS management for wider DNS work, or contact us to set one up.
How it works and what it costs
Domains are priced live in the client portal. DNS management and 10 mailboxes are included with dijihost Complete Hosting at £1 a day + VAT. On their own, DNS and email set-up is £45 an hour + VAT or a fixed quote.
Tell us what you have
Your domains, who they are registered with, where your DNS and email live today, and what you want to change.
Plan the change
We list every DNS record and mailbox first, so nothing is forgotten, and agree a time to switch.
Make the switch
Transfers, nameserver changes, DNS records and mailbox moves, done carefully with low TTLs and a rollback plan.
Check it works
We test the website, email delivery, SPF, DKIM and DMARC from the outside before calling it done.
Look after it
Renewals, records and email stay looked after, and you can call a person when something changes.
Frequently asked questions
Do I need to buy a subdomain?
No. Subdomains come free with the domain you already own. Any name in front of yourdomain.co.uk, such as shop or portal, can be created with a DNS record in your existing zone. dijitul sets them up for £45 an hour + VAT.
Should a subdomain use an A record or a CNAME?
Use an A record when the subdomain points at a server with a fixed IP address you control. Use a CNAME when a hosted platform gives you a hostname to point at, because they can change their addresses without you needing to update anything.
Can a subdomain have its own email?
Yes. A subdomain can have its own MX records to receive mail, and its own SPF and DKIM to send. This is common for marketing tools that send from a dedicated subdomain. Remember a subdomain that is a CNAME cannot also hold MX or TXT records.
Why does my new subdomain show a certificate warning?
The server or platform serving the subdomain does not yet have a certificate for that exact name. Many platforms issue one automatically once DNS is correct. If your DNS is in Cloudflare, the subdomain may need to be DNS only while the platform completes it.
What is subdomain delegation?
Delegation hands control of a subdomain to different nameservers by publishing NS records for it in your zone. The other provider then runs every record under that subdomain. It suits systems that need to manage their own DNS, while your main domain stays with you.
Related
Get domains, DNS and email sorted
Set up properly, records checked, and real people to call. DNS and email are included with dijihost hosting.