DNS function realization
1. DNS configures a forward lookup area to resolve domain names to IP addresses.
2. DNS configures a reverse lookup area to resolve IP addresses to domain names.
3. Domain name resolution classification:
A record: domain name > IP address
Cname record domain name > domain name
Mail Exchange record (MX) parses the mail server under the domain name
The pan-domain name resolution is preceded by a *
4. DNS polling supports web mirroring sites
One domain name corresponds to multiple IP addresses
5. Set DNS conditional forwarding
Forward the DNS resolution domain name condition configuration condition.
6. Set DNS as the transponder
Setting DNS as a transponder restricts the domain name resolution process, which is generally applicable to intranets or wide area networks
