What is the perfect DNS architecture?

One: DNS introduction: DNS is the abbreviation for the computer domain Name System, domain name, or domain Name service, which consists of a parser and a domain name server. A domain name server is a server that holds the domain name and corresponding IP address of all the hosts in the network and has the ability to convert domain names to IP addresses. Domain name and IP address between the conversion work called Domain name resolution, domain name resolution needs to be specialized domain name resolution server to complete, DNS is the domain name resolution server.

Second: The Hierarchical management mode of DNS: Each level of DNS server manages only its next level of DNS, as shown in the figure:

Three: DNS query process:

The first is local resolution: The client can respond in place using cached information, which is obtained through previous queries

The second is a recursive query: a set DNS server queries the other DNS servers on behalf of the client to fully resolve the name and return the results to the client.

The third is iterative query: The set DNS server returns to the client a different DNS server that can resolve the domain name, and the client continues to query the other DNS servers.

Four: Server types for DNS:

1: Primary DNS server: Records can be modified, deleted

2: Secondary DNS server: Copy records from primary DNS, cannot modify, delete.

3. Caching DNS servers:

4: Stub DNS servers: Domain name resolution for specific users

V: DNS resource records

SOA (starting authority): This record specifies the starting point for the zone. It contains information about the zone name, the zone administrator e-mail address, and instructions for how the secondary DNS server updates the zone data file settings, and so on

NS (name server): This record specifies the name server responsible for the given zone

A (host): This record lists the IP addresses of the specific host names.

CNAME (standard name): This record specifies the alias of the standard host name.

MX Mail exchanger records: This record lists the hosts responsible for receiving e-mail messages sent to the domain.

PTR (pointers): Maps IP addresses to domain names.