Type a web address into the browser, and the page opens quickly. In between, there is an invisible query: converting an easy-to-remember domain name into an address that network devices can recognize. This process is called domain name resolution.
Why this step is necessary
Devices on the network locate one another through a string of numeric addresses, while people are used to remembering names. Domain name resolution is the conversion between these two representations, and it is completed by a distributed query system spread around the world.
Which levels the query passes through
- Initiator: the device where the browser is running hands the domain name to a nearby resolution service to look it up.
- Local cache: the resolution service first checks whether it has already recorded this domain name. If it has and the record has not expired, it returns the result directly, and all subsequent steps are skipped.
- Root level: when it is not in the cache, the service queries the highest level and obtains the address of the server that governs the domain name's suffix.
- Suffix level: it queries downward and obtains the address of the server for the domain name itself.
- Authoritative level: the server for that domain name holds the specific records, and only here can the final result be obtained.
After the result is returned, it is cached along the way for a period of time. If the same query occurs again during this period, the entire process above does not need to be repeated. This is also why, after changing resolution settings, it sometimes takes a while for everything to take effect—the caches in various places need to expire before they query again.
Common record types
Resolution results are divided into several types according to purpose: those that point to a server address, an alias that points to another domain name, those that specify a mail server, those that specify the authoritative server for this domain name, and text records used to store verification information. Different purposes correspond to different types; simply choose as needed when configuring.
Problems that may occur
- Changes not taking effect: most often the cache has not yet expired, so waiting is enough; after confirming there is no mistake, you can contact the service provider to refresh the records.
- Resolution timeout: check whether the network is normal and whether the resolution service used by the local machine is available.
- Being pointed to the wrong address: this is a more serious situation. You need to use a trusted resolution service and verify whether the domain name's management authority is in your own hands.
A small reminder for enterprises
The management authority for domain names and resolution should be held by the enterprise in its own name. When a partner changes or contact information becomes invalid, whether management authority can be recovered depends on whose name these two items were registered under in the first place.