DNS, Nameservers and Caching
DNS connects a domain name to the services that use it. Nameservers identify where the DNS zone is managed, while individual records direct website traffic, email and verification requests.
Common DNS record types
- A: points a hostname to an IPv4 address.
- AAAA: points a hostname to an IPv6 address.
- CNAME: points one hostname to another hostname.
- MX: identifies the servers that receive email for the domain.
- TXT: stores text used for ownership checks and email authentication such as SPF and DKIM.
Follow Add a DNS Record when a provider has given you a record to publish.
Understand DNS caching
Each DNS record has a time to live, usually shown as TTL. This tells DNS resolvers how long they may keep a cached answer before checking again. After a change, some visitors may temporarily receive the previous answer until its earlier TTL expires. This is commonly described as DNS propagation.
Check a DNS change
- Confirm that you edited DNS at the provider named by the domain’s active nameservers.
- Check the record name, type and value against the instructions from the website, hosting or email provider.
- Allow for the previous TTL, then check the result using more than one network or a public DNS lookup tool.
- If only your device shows the old result, restart the browser or connection before changing the record again.
Changing DNS repeatedly can make the result harder to understand. Keep a note of each change and its time while testing.
Common questions
Frequently Asked Questions
Are nameservers and DNS records the same thing?
No. Nameservers identify where DNS is managed. DNS records are the individual instructions stored with that provider.
Why can two people see different versions of my website?
Their devices or DNS resolvers may still hold different cached answers. The earlier TTL usually determines how long the previous answer may remain in use.
Does changing website DNS also affect email?
It can if nameservers are changed without copying the existing email records. Updating only the correct website record is less likely to affect mail, but the full DNS zone should still be reviewed first.
Can I have more than one TXT record?
Yes. A domain can use several TXT records for different purposes, but some services impose their own rules. SPF, for example, should use one SPF policy for the same hostname.