The server industry is easy to say, and it is also easy to say. In the years of server development, it constantly summarizes and collates information. So today, our Micronet explains the classification of domain name servers: 1. Main domain name server: It is responsible for maintaining all domain name information in the region and is the authoritative information source of all specific information. In other words, the original data of this region is stored in the main domain name server, and the system administrator can modify it. 2. Secondary domain name server: When the primary domain name server fails, shuts down, or is overloaded, the secondary domain name server provides domain name resolution service as a backup service. The data in the zone file of the secondary domain name server is copied from another domain name server that is not directly imported. In other words, the region file is only a copy, and the data here is impossible. 3. Caching domain name server: It can run domain name server software, but does not have a domain name database. It gets the answer of each DNS query from a remote server. Once it gets the answer, it will be put into the cache, and later it will be used to answer the same information. The cached DNS server is not an authoritative server, because all the information provided is indirect information. 4. Forwarding domain name server: responsible for local query of all non local domain names. When the forwarding domain name server receives a query request, it will look up the request in its cache. If it cannot be found, the request will be forwarded to the specified domain name server in turn until the query result is found, otherwise unmapped results will be returned. I hope the summary of our DNS server can help you, and we look forward to cooperating with you, because we have a stronger after-sales team of DNS servers