Brief introduction of DNS
Common DNS records
SOA: Domain Authority Start
NS: authoritative domain name server
A: Host address
CNAME: The proper name of the alias
MX: Mail Delivery Server
PTR: Domain name pointer (for reverse DNS)
query process
Browser Cache->Hosts->LDNS->LDNS Cache->ISP->ISP Cache-> Root Server
Recursive/iterative queries
DNS and LDNS are usually iterative queries, LDNS has become a small errand boy, *** service
LDNS and public network authority DNS is usually recursive, high official: I don't know, this should be the work of Dumby, you go to Dumby
