Move from explanation to action with the matching DomainCheck.co.uk tools for this topic.
Check live resolution before and after a DNS or transfer change.
Useful when a UK domain transfer depends on TAG or registrar handling.
Check TLD context when transfer and DNS behaviour can vary by namespace.
Many DNS issues start with a simple choice between an A record and a CNAME. People searching for this topic usually want to know which one to use for a website, what the technical difference is, and why some setups allow one but not the other. That is a different intent from general DNS propagation or email records, so it deserves its own focused article.
A records and CNAME records both help DNS point a name to a destination, but they do it in different ways.
An A record points a hostname directly to an IPv4 address. A CNAME record points one hostname to another hostname. That sounds small, but it changes how the DNS lookup works and where each record can be used.
An A record is the direct mapping many websites use. If someone types your domain into a browser, the A record can tell DNS which IP address should receive the request.
This is useful when:
Because it points to an IP address, an A record is straightforward. If the IP changes, you update the record to the new address.
A CNAME record is an alias. Instead of pointing to an IP address, it points one hostname to another hostname.
This is useful when:
For example, a www hostname might CNAME to the root domain or to a platform-specific hostname. That way, if the target changes behind the scenes, you may only need to update the canonical destination.
The simplest way to remember it is:
That distinction matters because DNS still has to resolve the final destination. A CNAME adds an extra step in the lookup chain, while an A record is direct.
| Topic | A record | CNAME |
|---|---|---|
| Points to | An IP address | Another hostname |
| Best fit | Direct hosting and apex domains | Aliases and managed subdomains |
| Root domain | Common | Usually provider-specific or not allowed |
| Lookup path | Direct | One extra resolution step |
This is where people usually get tripped up.
The root domain, sometimes called the apex domain, is the bare domain without a prefix. The www version is a subdomain.
In many DNS setups, a CNAME cannot be used at the root domain because the root also has to carry other records, such as NS and SOA. Some DNS providers support special alias-like features that behave similarly to a CNAME at the apex, but that is provider-specific rather than universal.
So in practice:
That is a common and sensible pattern, but not the only one.
You know the IP address, the host wants direct mapping, or you are configuring the apex domain.
The platform gives you a hostname target or the hostname should follow a canonical destination.
The provider’s docs mention aliasing, flattening, or special apex support.
One hostname should have one clear DNS job. Mixing instructions creates avoidable errors.
Use an A record if:
Use a CNAME if:
If your provider gives exact instructions, follow those instructions rather than forcing a generic pattern. DNS providers and platforms vary.
The most common mistake is configuring the root domain and www as if they were the same hostname. They are not. If one works and the other does not, the record types may not match the provider’s expectations.
The most common mistakes are:
If both an A record and a CNAME exist for the same hostname, the result may be invalid or ignored depending on the DNS system. As a rule, keep one clear purpose per hostname.
If a service uses IPv6, you may also see AAAA records. These are similar in spirit to A records, but they point to an IPv6 address instead of IPv4. They are not the same as CNAMEs, and they do not replace the direct-versus-alias decision.
When you update an A record, the hostname can start resolving to a new IP as the change propagates through caches.
When you update a CNAME, the alias can begin pointing to a new destination hostname. That new target may itself have its own DNS records and caching behaviour.
That means a CNAME-based setup can sometimes involve an extra layer of waiting or troubleshooting, because the final answer depends on the alias target as well as the alias itself.
Neither record is better for SEO on its own. Search engines care about the site’s accessibility, stability, and implementation, not whether you used an A record or a CNAME. The right choice is the one that matches the technical requirements of your hosting or platform.
If you are unsure, ask:
That is usually enough to choose correctly.