目录




DNS

DNS(Domain Name System，域名系统)，在Internet上作为域名和IP地址映射的一个分布式数据库，能够使用户更直观、更方便的访问互联网(域名更便于记忆)，而不用去记住能够被机器直接读取的IP地址。通过主机名，最终得到该主机名对应的IP地址的过程叫做域名解析(或主机名解析)。所以DNS服务器的功能既是：​域名、IP映射​，DNS协议运行在UDP协议之上，使用端口号53。

​hostname到IPaddress映射有两种方式​：

1) 静态映射，每台设备上都配置主机到IP地址的映射(hosts)，各设备独立维护自己的映射表，而且只供本设备使用；

2) 动态映射，建立一套域名解析系统(DNS)，只在专门的DNS服务器上配置主机到IP地址的映射，网络上需要使用主机名通信的设备，首先需要到DNS服务器查询主机所对应的IP地址。

​注意​：在解析域名时，可以首先采用静态域名解析的方法，如果静态域名解析不成功，再采用动态域名解析的方法。可以将一些常用的域名放入静态域名解析表中，这样可以大大提高域名解析效率。

DNS Server

ServerSite

vim named.conf

opeions {
    #    listen-on port 53 { 127.0.0.1; }; #Monitoring computer IP. General Comment.
    #    listen-on-v6 post 53 { ::1; };  #As above
        directory     "/etc/named";  #specify directory of store domain data coinfig file
        allow-query { any; };  #specify DNSServer response network segment, 'any' mean that all network segment.
    };
    zone "." IN {
        type hint;
        file "name.ca"; #record 13 root DNSServerIP
    }

Master DNS Server

​step1​.

yum install -y bind bind-chroot

​step2​. Edit the config file.

vim /etc/named.conf

opeions {
        #    listen-on port 53 { 127.0.0.1; }; #monitoring computer IP, General comments.
        #    listen-on-v6 post 53 { ::1; }; #Idem
            directory     "/etc/named";  #specify directory of store domain data coinfig file
            allow-query { any; };   #specify DNSServer response network segment, any mean that all network segment.
        };

Forward Domain

vim /etc/name.rf1912.zone

zone "fan.com" IN {
                type master;
                file "fan.com.zone";  #need create in the /var/named/fan.com.zone by manual
                allow-update { none; };
            };

Create zone config file:

cp -p /var/named/named.localhost /var/named/fan.com.zone

vim fan.com.zone

@        NS    hostname.domain.   #one NS flag have to mapping one A flay
            hostname    A    192.168.1.144
            www        A    192.168.1.145
            ftp        A    192.168.1.146
            @        MX    10    mail.fan.com.

Reverse Resolution

vim /etc/name.rf1912.zone

zone "1.168.192.in-addr.arpa" IN {
                type master;
                file "192.168.1.zone";
                allow-update { none; };
            };

Create zone config file:

cp -p /var/named/named.localhost /var/named/192.168.1.zone

vim 192.168.1.zone

@        NS     hostname.domain.
            145        PTR  www.fan.com.
            146        PTR     ftp.fan.com.

​step3​. Start named service

service named restart

Slave DNS Server

​step1​. Edit Slave dns server’s named.conf file same as master server

​step2​. Edit the named.rf1912.zones

Forward lookup:

vim /etc/named.rf1912.zones

zone "fan.com" IN {
                type slave;
                masters { MasterServerIP; };
                file "slaves/fan.com.zone.slave";  #in the /var/names/slaves/ directory
            };

Reverse lookup:

vim /etc/named.rf1912.zones

zone "1.168.192.in-addr.arpa" IN {
                type slave;
                masters { MasterServerIP; };
                file "slaves/192.168.1.zone.slave";
            };

​step3​. 

service named restart

Split DNS Server

​step1​. Edit the DNSServer main config file

vim /etc/named.conf 

#Comment the root node and line of 'include "/etc/named.rf1912.zone"'
        #zone "." IN {
        #       type hint;
        #       file "named.ca";
        #};
        #include "/etc/named.rf1912.zone"

​step2​. Add view for public network and private network

Attention:First setting LAN then setting WAN .

vim /etc/named.conf

​privateNetwork​：

view "lan(viewName)" {
            match-clients { 1992.168.1.0/24; };   #specify split uplook domain networkSepment.
            zone "fan.com" IN {       #define the uplook domain
                type master;
                file "fan.com.zone"
                notify yes;     #allow tthe DNSServer update
                also-notify { 192.168.1.2; };    #assign to the dns slave server
            };
        };

​publicNetwork​

view "wan" {
            match-clients { any; };
            zone "fan.com" IN {
                type master;
                file "fan.com.zone"
            };
        };

​step3​. Create the domain date file in directory with “/var/named” and restart named service.