DNS domain name resolution

Catalog

 DNS

DNS The role of

DNS Query mode of

DNS Domain name system

The process

build DNS Domain name resolution server

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 DNS

Domain name management system DNS(Domain Name System) It means domain name resolution server , Application layer protocol , Is a service of the Internet . It can be used to IP A distributed database with address mapping , Can make people more convenient access to the Internet , Instead of remembering what can be read directly by the machine IP Number string .

DNS The role of

Forward analysis ： Domain name converted to IP  A Record
Reverse DNS ：IP Convert to domain name  P Record

DNS Query mode of

1 recursive query
Recursive query is a kind of DNS The query mode of the server , In this mode DNS
The server received a client request , You must reply to the client with an accurate query result .
If DNS The server does not store queries locally DNS Information , Then the server will ask other servers ,
And submit the returned query results to the client

2 Iterative query
DNS Another query method of the server is iterative query , When the client sends a query request ,DNS The server
Do not reply directly to the query results , Instead, tell the client another DNS Server address , Client redirection
The machine DNS The server submits the request , Loop back and forth until the result of the query is returned

DNS Domain name system

 

The process

1 First check the cache record of this machine
2 Inquire about hosts file
3 Inquire about dns Domain name server , hand dns Domain name server processing
4 This dns The server may be a local domain name server . There's also caching , If there is a direct return result , If not, proceed to the next step
5 Help the root domain server , The root domain server returns the top-level server that may know the result and asks him to find the top-level server
6 Help the top-level domain server , The top-level server returns the secondary domain server that may know the result and asks him to find the server
7 Turn to the secondary domain server , The secondary domain server found that it is my host , Find out ip The address is returned to the local domain name server
8 The local domain name server logs the results to the cache , Then put the domain name and ip The corresponding relationship is returned to the client

build DNS Domain name resolution server

Install the software bind

Turn off firewall

vim /etc/named.conf  Modify global profile

Listening address We changed it to local

Which network segments can be used DNS service

 

 vim /etc/named.rfc1912.zones  Modify area profile

Forward analysis “yanxiaoyun.com" Area

The specified area data file is yanxiaoyun.com.zone

Configure forward zone data file

 cd /var/named/

cp -p named.localhost yanxiaoyun.com.zone

 wq preservation

systemstl start named ## start-up DNS

Switch to another host for testing