A DNS server has a hierarchical structure with a root. On the same domain, you can attach several sub-domains and delegations (data records in the sub-domain’s parent zone) to other servers. There are a number of ramifications to these actions. If the sub-domains are not delegated, they create DNS zones. These are sets of domains and sub-domains grouped on the same server. The most commonly used DNS server type on the internet is the BIND server. The domain names located directly under the root directory are the primary domains, also called ‘top-level domains’ (TLDs). The extensions are distributed as follows:
- generic top-level domains (gTLDs), e.g. .com or .org
- country code top-level domains (ccTLDs), e.g. .uk or .fr
- secondary level domain names For further information on this topic, please refer to our guide on managing your DNS zone