The following are some common DNS issues you might consider if you are experiencing issues with your domain (be sure to check out our Why is my domain not working? FAQ entry if you aren't sure the problem is at the DNS level):
- Recent DNS changes and propagation: Always bear in mind that the DNS system functions by caching queries - this means that whenever you make a DNS update it takes time to 'propagate' across local DNS caches around the world, and this usually takes around 24 hours. During this time, from any given location you might get a new DNS response or you might get a cached one from your network or ISP's local DNS servers.
- Problem with the delegation at the registry: Check the WHOIS to make sure the correct name servers are listed to your domain. Please note that some registries have name server configuration requirements and so if you have submitted a delegation with us that isn't showing at the WHOIS it may have been rejected by the registry; we will have notified you via email in this case so please check your emails and also check this FAQ for further details regarding DNS requirements for specific domain extensions.
- Name servers aren't configured to answer for the domain: Even if your domain is delegated to the right name servers at the registry, if these name servers aren't set up to answer for your domain your domain will not resolve and none of the services at your domain will function correctly. If you are familiar with tools such as dig (domain information groper) or nslookup you can query your name servers and see if they are answering queries for your domain and resolving services at your domain to the right place or not; or contact your name server provider for assistance in checking.
- '@' Host CNAME Records: Please note that many issues can be caused by the inclusion of an '@' host CNAME (that is, a CNAME for your 'bare' domain, e.g. "yourdomainname.com").
Because of how CNAME records work and resolve in the DNS system they will prevent the correct resolution of any other DNS records for the same host. For the '@' host this includes MX records, NS records and the SOA itself and so the issues caused can be extensive (notably your MX records not resolving will halt incoming mail). Your bare domain name should always resolve (if it resolves anywhere) via A record (or AAAA record) to an IP address - a common solution is to redirect your bare domain name to the 'www' host and have this 'www' host resolve via CNAME.