Linux 下DNS详解

配置之前先了解一下bind DNS服务器软件：BIND是一种开源的DNS（Domain Name System）协议的实现，包含对域名的查询和响应所需的所有软件。它是互联网上最广泛使用的一种DNS服务器，对于类UNIX系统来说，已经成为事实上的标准。

为了构架DNS服务器来解析域名或ip地址，我们得安装BIND和caching-nameserver。为了TCP和UDP53数据包能通过，我们也有必要配置路由器。

安装 BIND 软件包

1、安装

# yum -y install bind caching-nameserver

2、配置

下面的例子是以公网IP（172.16.0.80/29），局域网IP（192.168.0.0/24），域名（linuxde.net）作说明。在配置你自己的服务器时，请使用你自己的IP和域名。

# vim /etc/named.conf

options {

directory "/var/named";

# query range

allow-query { localhost; 192.168.0.0/24; };

# transfer range

allow-transfer { localhost; 192.168.0.0/24; };

# recursion range

allow-recursion { localhost; 192.168.0.0/24; };

};

controls {

inet 127.0.0.1 allow { localhost; } keys { rndckey; };

};

# here is the section for internal informations

vimew "internal" {

match-clients {

localhost;

192.168.0.0/24;

};

zone "." IN {

type hint;

file "named.ca";

};

# set zones for internal

zone "linuxde.net" IN {

type master;

file "linuxde.net.lan";

allow-update { none; };

};

# set zones for internal

zone "0.168.192.in-addr.arpa" IN {

type master;

file "0.168.192.db";

allow-update { none; };

};

zone "localdomain" IN {

type master;

file "localdomain.zone";

allow-update { none; };

};

zone "localhost" IN {

type master;

file "localhost.zone";

allow-update { none; };

};

zone "0.0.127.in-addr.arpa" IN {

type master;

file "named.local";

allow-update { none; };

};

zone "255.in-addr.arpa" IN {

type master;

file "named.broadcast";

allow-update { none; };

};

zone "0.in-addr.arpa" IN {

type master;

file "named.zero";

allow-update { none; };

};

};

vimew "external" {

match-clients {

any;

};

zone "." IN {

type hint;

file "named.ca";

};

# set zones for external

zone "linuxde.net" IN {

type master;

file "linuxde.net.wan";

allow-update { none; };

};

# set zones for external *note

zone "80.0.16.172.in-addr.arpa" IN {

type master;

file "80.0.16.172.db";

allow-update { none; };

};

};

include "/etc/rndc.key";

# *note : For How to write for reverse resolvimng, Write network address reversely like below.

the case for 192.168.0.0/24

network address? 192.168.0.0

range of network? 192.168.0.0 - 192.168.0.255

how to write? 0.168.192.in-addr.arpa

case of 172.16.0.80/29

network address? 172.16.0.80

range of network? 172.16.0.80 - 172.16.0.87

how to write? 80.0.16.172.in-addr.arp

设置Zones

创建zone文件以便服务器能解析域名IP。

1、内部zone文件

这个例子使用的是内网地址（192.168.0.0/24），域名(linuxde.net)，请根据自己的具体情况配置。

# vim /var/named/linuxde.net.lan

$TTL    86400

@        IN    SOA   ns.linuxde.net. root.linuxde.net. (

               2007041501   ;Serial

               3600         ;Refresh

               1800         ;Retry

               604800       ;Expire

               86400        ;Minimum TTL

)

               # define name server

               IN    NS     ns.linuxde.net.

               # internal IP address of name server

               IN    A       192.168.0.17

               # define mail exchanger

               IN    MX 10   ns.linuxde.net.

               # define IP address and hostname

ns             IN    A       192.168.0.17

2、外部zone文件

这个例子使用的是外网地址（172.16.0.80/29），域名（linuxde.net），请替换成自己的。

# vim /var/named/linuxde.net.wan

$TTL      86400

@          IN    SOA    ns.linuxde.net. root.linuxde.net. (

                 2007041501    ;Serial

                 3600          ;Refresh

                 1800          ;Retry

                 604800        ;Expire

                 86400         ;Minimum TTL

)

                 # define name server

                 IN        NS   ns.linuxde.net.

                 # external IP address of name server

                 IN        A    172.16.0.82

                 # define Mail exchanger

                 IN        MX 10 ns.linuxde.net.

                 # define IP address and hostname

ns               IN        A     172.16.0.82

创建zone文件使服务器能够反向解析IP到域名。

3、内部zone文件

这个例子使用的是内网地址（192.168.0.0/24），域名（linuxde.net），请使用自己的设置替换。

# vim /var/named/0.168.192.db

$TTL    86400

@       IN    SOA  ns.linuxde.net. root.linuxde.net. (

              2007041501     ;Serial

              3600           ;Refresh

              1800           ;Retry

              604800         ;Expire

              86400          ;Minimum TTL

)

              # define name server

              IN        NS    ns.linuxde.net.

              # define range that this domain name in

              IN        PTR   linuxde.net.

              # define IP address and hostname

              IN        A     255.255.255.0

17            IN        PTR   ns.linuxde.net.

4、外部zone文件

这例子使用外网地址（172.16.0.80/29），域名（linuxde.net），请替换成自己的。

# vim /var/named/80.0.16.172.db

$TTL     86400

@        IN    SOA  ns.linuxde.net. root.linuxde.net. (

               2007041501     ;Serial

               3600           ;Refresh

               1800           ;Retry

               604800         ;Expire

               86400          ;Minimum TTL

)

               # define name server

               IN        NS   ns.linuxde.net.

               # define range that this domain name in

               IN        PTR  linuxde.net.

               # define IP address and hostname

               IN        A     255.255.255.248

82             IN        PTR   ns.linuxde.net.

启动BIND

1、完成BIND的配置后，在启动named之前，还需要建立chroot环境。

# yum -y install bind-chroot
# /etc/rc.d/init.d/named start
# chkconfig named on

2、操作检验

确认服务器已经正确解析域名或IP地址。

# dig ns.linuxde.net.
; <<>> DiG 9.3.4 <<>> ns.linuxde.net.
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 54592
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;ns.linuxde.net.           IN   A

;; ANSWER SECTION:
ns.linuxde.net. 86400   IN   A    192.168.0.17

;; AUTHORITY SECTION:
linuxde.net.     86400   IN   NS   ns.linuxde.net.

;; Query time: 0 msec
;; SERVER: 192.168.0.17#53(192.168.0.17)
;; WHEN: Thu Mar 8 19:35:19 2007
;; MSG SIZE rcvd: 68

# dig -x 192.168.0.17
; <<>> DiG 9.3.4 <<>> -x 192.168.0.17
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 45743
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 1

;; QUESTION SECTION:
;17.0.168.192.in-addr.arpa.           IN   PTR

;; ANSWER SECTION:
17.0.168.192.in-addr.arpa. 86400   IN   PTR   ns.linuxde.net.

;; AUTHORITY SECTION:
0.168.192.in-addr.arpa.     86400   IN   NS     ns.linuxde.net.

;; ADDITIONAL SECTION:
ns.linuxde.net.          86400   IN   A       192.168.0.17

;; Query time: 0 msec
;; SERVER: 192.168.0.17#53(192.168.0.17)
;; WHEN: Thu Mar 8 19:37:50 2007
;; MSG SIZE rcvd: 107

配置从DNS服务器

配置从DNS服务器比较简单。下面的例子主DNS是“ns.linuxde.net”，从DNS是“ns.example.info”。

1、在主DNS服务器的zone文件作如下配置

# vim /var/named/linuxde.net.wan

$TTL     86400

@        IN   SOA   ns.linuxde.net. root.linuxde.net. (

              # update serial

              2007041501      ;Serial

              3600            ;Refresh

              1800            ;Retry

              604800          ;Expire

              86400           ;Minimum TTL

)

              IN         NS   ns.linuxde.net.

              # add name server

              IN         NS   ns.example.info.

              IN         A    172.16.0.82

              IN         MX 10 ns.linuxde.net.

ns            IN         A    172.16.0.82

# rndc reload
server reload successful

2、配置从DNS服务器

# vim /etc/named.conf

# add these lines below
    zone "linuxde.net" IN {
          type slave;
          masters { 172.16.0.82; };
          file "slaves/linuxde.net.wan";
};

# rndc reload
server reload successful
# ls /var/named/slaves
linuxde.net.wan # zone file in master DNS has been just transfered

设置别名记录，如果你想为你的主机设置另一个名称，在zone文件定义CNAME记录

# vim /var/named/server-Linux.info.wan

$TTL    86400

@       IN    SOA   ns.server-linux.info. root.server-linux.info. (

              # update serial

              2007041501      ;Serial

              3600            ;Refresh

              1800            ;Retry

              604800          ;Expire

              86400           ;Minimum TTL

)

              IN        NS    ns.server-linux.info.

              IN        A     172.16.0.82

              IN        MX 10 ns.server-linux.info.

ns            IN        A     172.16.0.82

# aliase IN CNAME server's name

ftp          IN       CNAME   ns.server-linux.info.