在oracle 11g的RAC中增加了SCAN IP,而使用 SCAN IP的一种方式就是使用DNS，这里介绍在Redhat Linux 5.4中DNS的详细配置操作
在配置DNS之前修改主机名
Redhat linux 5.4 DNS配置操作
在配置DNS之前修改主机名
[root@beiku1 etc]# hostname beiku1.sbyy.com [root@beiku1 etc]# vi /etc/hosts # Do not remove the following line, or various programs # that require network functionality will fail. 127.0.0.1 beiku1.sbyy.com localhost ::1 localhost6.localdomain6 localhost6 10.138.130.161 beiku1 [root@beiku1 etc]# vi /etc/sysconfig/network NETWORKING=yes NETWORKING_IPV6=no HOSTNAME=beiku1.sbyy.com GATEWAY=10.138.130.254
一.安装软件包
Redhat linux 5.4 下的dns服务所有的bind包如下：
bind-9.3.6-4.P1.el5 bind-libbind-devel-9.3.6-4.P1.el5 kdebindings-devel-3.5.4-6.el5 kdebindings-3.5.4-6.el5 bind-devel-9.3.6-4.P1.el5 bind-utils-9.3.6-4.P1.el5 bind-chroot-9.3.6-4.P1.el5 ypbind-1.19-12.el5 system-config-bind-4.0.3-4.el5 bind-libs-9.3.6-4.P1.el5 bind-sdb-9.3.6-4.P1.el5
使用rpm –qa | grep bind来检查系统是否已经安装了以上软件包:
[root@beiku1 soft]# rpm -qa | grep bind bind-chroot-9.3.6-4.P1.el5 kdebindings-3.5.4-6.el5 ypbind-1.19-12.el5 bind-libs-9.3.6-4.P1.el5 bind-9.3.6-4.P1.el5 system-config-bind-4.0.3-4.el5 bind-utils-9.3.6-4.P1.el5
对于没有安装的软件包执行以下命令进行安装
[root@beiku1 soft]# rpm -ivh bind-9.3.6-4.P1.el5.i386.rpm
warning: bind-9.3.6-4.P1.el5.i386.rpm: Header V3 DSA signature: NOKEY, key ID 37017186
Preparing... ########################################### [100%]
package bind-9.3.6-4.P1.el5.i386 is already installed
[root@beiku1 soft]# rpm -ivh caching-nameserver-9.3.6-4.P1.el5.i386.rpm
warning: caching-nameserver-9.3.6-4.P1.el5.i386.rpm: Header V3 DSA signature: NOKEY, key ID 37017186
Preparing... ########################################### [100%]
1:caching-nameserver ########################################### [100%]
[root@beiku1 soft]# rpm -ivh install kdebindings-devel-3.5.4-6.el5.i386.rpm
error: open of install failed: No such file or directory
warning: kdebindings-devel-3.5.4-6.el5.i386.rpm: Header V3 DSA signature: NOKEY, key ID 37017186
[root@beiku1 soft]# rpm -ivh kdebindings-devel-3.5.4-6.el5.i386.rpm
warning: kdebindings-devel-3.5.4-6.el5.i386.rpm: Header V3 DSA signature: NOKEY, key ID 37017186
Preparing... ########################################### [100%]
1:kdebindings-devel ########################################### [100%]
[root@beiku1 soft]# rpm -ivh bind-sdb-9.3.6-4.P1.el5.i386.rpm
warning: bind-sdb-9.3.6-4.P1.el5.i386.rpm: Header V3 DSA signature: NOKEY, key ID 37017186
Preparing... ########################################### [100%]
1:bind-sdb ########################################### [100%]
[root@beiku1 soft]# rpm -ivh bind-libbind-devel-9.3.6-4.P1.el5.i386.rpm
warning: bind-libbind-devel-9.3.6-4.P1.el5.i386.rpm: Header V3 DSA signature: NOKEY, key ID 37017186
Preparing... ########################################### [100%]
1:bind-libbind-devel ########################################### [100%]
[root@beiku1 soft]# rpm -ivh bind-devel-9.3.6-4.P1.el5.i386.rpm
warning: bind-devel-9.3.6-4.P1.el5.i386.rpm: Header V3 DSA signature: NOKEY, key ID 37017186
Preparing... ########################################### [100%]
1:bind-devel ########################################### [100%]
还要手动安装一个软件包caching-nameserver-9.3.6-4.P1.el5 ,不安装这个软件包named服务不能启动,会报错误信息 例如:
[root@beiku1 ~]# service named start Locating /var/named/chroot//etc/named.conf failed: [FAILED] [root@beiku1 soft]# rpm -ivh caching-nameserver-9.3.6-4.P1.el5.i386.rpm warning: caching-nameserver-9.3.6-4.P1.el5.i386.rpm: Header V3 DSA signature: NOKEY, key ID 37017186 Preparing... ########################################### [100%] 1:caching-nameserver ########################################### [100%] [root@beiku1 soft]# service named start Starting named: [ OK ]
二.复制模板文件
由于安装了chroot环境，所以我们的DNS主配置文件应该在/var/named/chroot/etc目录下面
[root@beiku1 soft]# cd /var/named/chroot/ [root@beiku1 chroot]# ls dev etc proc var [root@beiku1 chroot]# cd etc [root@beiku1 etc]# ls localtime named.caching-nameserver.conf named.rfc1912.zones rndc.key [root@beiku1 etc]#
named.caching-nameserver.conf文件内容如下:
[root@beiku1 etc]# cat named.caching-nameserver.conf
//
// named.caching-nameserver.conf
//
// Provided by Red Hat caching-nameserver package to configure the
// ISC BIND named(8) DNS server as a caching only nameserver
// (as a localhost DNS resolver only).
//
// See /usr/share/doc/bind*/sample/ for example named configuration files.
//
// DO NOT EDIT THIS FILE - use system-config-bind or an editor
// to create named.conf - edits to this file will be lost on
// caching-nameserver package upgrade.
//
options {
listen-on port 53 { 127.0.0.1; };
listen-on-v6 port 53 { ::1; };
directory "/var/named";
dump-file "/var/named/data/cache_dump.db";
statistics-file "/var/named/data/named_stats.txt";
memstatistics-file "/var/named/data/named_mem_stats.txt";
// Those options should be used carefully because they disable port
// randomization
// query-source port 53;
// query-source-v6 port 53;
allow-query { localhost; };
allow-query-cache { localhost; };
};
logging {
channel default_debug {
file "data/named.run";
severity dynamic;
};
};
view localhost_resolver {
match-clients { localhost; };
match-destinations { localhost; };
recursion yes;
include "/etc/named.rfc1912.zones";
};
这个文件告诉我们不要直接的编辑这个文件，去创建一个named.conf文件，然后编辑named.conf文件，当有了named.conf，将不在读取这个文件。现在就将named.caching-nameserver.conf文件复制成named.conf文件。
[root@beiku1 etc]# cp -p named.caching-nameserver.conf named.conf [root@beiku1 etc]# ls localtime named.caching-nameserver.conf named.conf named.rfc1912.zones rndc.key
可以看到，named.conf文件就被创建成功了。最好在copy的时候加上-P的参数，保留权限。否则启动服务的时候会报权限拒绝的。
三.编辑named.conf文件
[root@beiku1 etc]# vi named.conf
//
// named.caching-nameserver.conf
//
// Provided by Red Hat caching-nameserver package to configure the
// ISC BIND named(8) DNS server as a caching only nameserver
// (as a localhost DNS resolver only).
//
// See /usr/share/doc/bind*/sample/ for example named configuration files.
//
// DO NOT EDIT THIS FILE - use system-config-bind or an editor
// to create named.conf - edits to this file will be lost on
// caching-nameserver package upgrade.
//
options {
listen-on port 53 { any; };
listen-on-v6 port 53 { ::1; };
directory "/var/named";
dump-file "/var/named/data/cache_dump.db";
statistics-file "/var/named/data/named_stats.txt";
memstatistics-file "/var/named/data/named_mem_stats.txt";
// Those options should be used carefully because they disable port
// randomization
// query-source port 53;
// query-source-v6 port 53;
allow-query { 10.138.130.0/24; };
allow-query-cache { any; };
};
logging {
channel default_debug {
file "data/named.run";
severity dynamic;
};
};
view localhost_resolver {
match-clients { 10.138.130.0/24; };
match-destinations { any; };
recursion yes;
include "/etc/named.rfc1912.zones";
};
解释这些语法参数的意思
options
代表全局配置
listen-on port 53 { any; };
DNS服务监听在所有接口
listen-on-v6 port 53 { ::1; };
ipv6监听在本地回环接口
directory “/var/named”;
zone文件的存放目录，指的是chroot环境下面的/var/named
dump-file “/var/named/data/cache_dump.db”;
存放缓存的信息
statistics-file “/var/named/data/named_stats.txt”;
统计用户的访问状态
memstatistics-file “/var/named/data/named_mem_stats.txt”;
每一次访问耗费了多数内存的存放文件
allow-query { 10.138.130.0/24 };
允许查询的客户端，现在修改成本地网段，
allow-query-cache {any; };
允许那些客户端来查询缓存,any表示允许任何人。
logging {
channel default_debug {
file “data/named.run”;
severity dynamic;
};
定义日志的存放位置在/var/named/chroot/var/named/data/目录下面
};
view localhost_resolver {
match-clients { 10.138.130.0/24; };
match-destinations { any; };
recursion yes;
include “/etc/named.rfc1912.zones”;
};
这里是定义视图的功能,
Match-clients 是指匹配的客户端
Match-destination 是指匹配的目标
到这里，named.conf文件就已经配置成功了，这个视图最后写include “/etc/named.rfc1912.zones”;接下面，就去配置这个文件。当然，我们可以匹配不同的客户端来创建不同的视图。
四.定义zone文件
[root@beiku1 etc]# vi named.rfc1912.zones
// named.rfc1912.zones:
//
// Provided by Red Hat caching-nameserver package
//
// ISC BIND named zone configuration for zones recommended by
// RFC 1912 section 4.1 : localhost TLDs and address zones
//
// See /usr/share/doc/bind*/sample/ for example named configuration files.
//
zone "." IN {
type hint;
file "named.ca";
};
zone "sbyy.com" IN {
type master;
file "sbyy.zone";
allow-update { none; };
};
zone "130.138.10.in-addr.arpa" IN {
type master;
file "named.sbyy";
allow-update { none; };
};
解释这些语法参数的意思
Zone “.” 根区域
Zone “sbyy.com” 定义正向解析的区域
zone “130.138.10.in-addr.arpa” 定义反向解析的区域
IN Internet记录
type hint 根区域的类型为hint
type master 区域的类型为主要的
file “named.ca” ; 区域文件是named,ca
file “sbyy.zone”; 指定正向解析的区域文件是sbyy.zone
file “named.sbyy”; 指定反向解析的区域文件是named,sbyy
allow-update { none; }; 默认情况下，是否允许客户端自动更新
在named.ca文件中就定义了全球的13台根服务器，
在sbyy.com文件中就定义DNS的正向解析数据库
在named.sbyy文件中就定义DNS反向解析的数据库
定义zone文件就完成了，下面来编辑DNS的数据库文件。
五.使用模板文件来创建数据库文件
[root@beiku1 etc]# cd /var/named/chroot/var/named/ [root@beiku1 named]# ls data localdomain.zone localhost.zone named.broadcast named.ca named.ip6.local named.local named.zero slaves
可以看到，在chroot环境下面的/var/named/有很多模板文件。Named.ca就是根区域的数据库文件，我们将localhost.zone复制成sbyy.zone，这个是正向解析的数据库文件，将named.local复制成named.sbyy，这个是反向解析的数据库文件。数据库文件一定要和/etc/named.rfc1912.zones这个文件里面的匹配。
[root@beiku1 named]# cp -p localhost.zone sbyy.zone [root@beiku1 named]# cp -p named.local named.sbyy [root@beiku1 named]# ls data named.broadcast named.local sbyy.zone localdomain.zone named.ca named.sbyy slaves localhost.zone named.ip6.local named.zero
复制成功，正向解析和反向解析的数据库文件就创建完成了。
六.定义数据库文件
1. 定义正向解析数据库文件
[root@beiku1 named]# vi sbyy.zone
$TTL 86400
@ IN SOA beiku1.sbyy.com. root.sbyy.com. (
44 ; serial (d. adams)
3H ; refresh
15M ; retry
1W ; expiry
1D ) ; minimum
@ IN NS beiku1.sbyy.com.
beikuscan IN A 10.138.130.167
beikuscan IN A 10.138.130.168
beikuscan IN A 10.138.130.169
beiku2 IN A 10.138.130.162
beiku1 IN A 10.138.130.161
关于正向解析数据库中每一行参数的解释
$TTL 86400
最小的存活的时间是86400S（24H）
@ IN SOA @ root (
这是一笔SOA记录，只允许存在一个SOA记录
@是代表要解析的这个域本身()
IN是Internet记录。
SOA 是初始授权记录，指定网络中第一台DNS Server。
root是指管理员的邮箱。
44 ; serial (d. adams)
3H ; refresh
15M ; retry
1W ; expiry
1D ) ; minimum
这些部分主要是用来主DNS和辅助DNS做同步用的
44 序列号，当主DNS数据改变时，这个序列号就要被增加1，而辅助DNS通过序列号来和主DNS同步。
3H 刷新，主DNS和辅助DNS每隔三小时同步一次。
15M 重试，3H之内，没有同步，每隔15M在尝试同步
1W 过期，1W之内，还没有同步，就不同步了
1D 生存期，没有这条记录，缓存的时间。
@ IN NS beiku1.sbyy.com.
这是一笔NS记录，指定nameserver为beiku1.sbyy.com至少要有一笔NS记录
beiku1 IN A 10.138.130.161
指定beiku1的ip地址为10.138.130.161
beikuscan IN A 10.138.130.167
指定beikuscan的ip地址为10.138.130.167
beikuscan IN A 10.138.130.168
指定beikuscan的ip地址为10.138.130.168
beikuscan IN A 10.138.130.169
指定beikuscan的ip地址为10.138.130.169
beiku2 IN A 10.138.130.162
指定beiku2的ip地址为10.138.130.162
正向解析的数据库就完成了，下面定义反向解析的数据库。
2. 定义反向解析数据库
[root@beiku1 named]# vi named.sbyy
$TTL 86400
@ IN SOA beiku1.sbyy.com. root.sbyy.com. (
1997022702 ; Serial
120 ; Refresh
120 ; Retry
3600000 ; Expire
86400 ) ; Minimum
@ IN NS beiku1.sbyy.com.
167 IN PTR beikuscan.sbyy.com.
168 IN PTR beikuscan.sbyy.com.
169 IN PTR beikuscan.sbyy.com.
162 IN PTR beiku2.sbyy.com.
161 IN PTR beiku1.sbyy.com.
其实反向解析的数据库文件的配置和正向解析的差不多，只需要将ip地址和域名换一个位置就可以了，把A换成PTR就ok了。
DNS的基本配置就完成了，在来看看DNS是否能够正常工作。
我们先重启一下DNS服务
[root@beiku1 etc]# service named restart Stopping named: [ OK ] Starting named: [ OK ]
可以看到，DNS服务启动成功了。
在查询以前，要在客户端来指定DNS Server，在/etc/resolv.conf这个文件中指定。
[root@beiku1 etc]# vi /etc/resolv.conf search sbyy.com nameserver 10.138.130.161 [root@beiku1 etc]# service named restart Stopping named: [ OK ] Starting named: [ OK ]
参数及意义:
nameserver 表明dns 服务器的ip 地址，可以有很多行的nameserver，每一个带一个ip地址。
在查询时就按nameserver 在本文件中的顺序进行，且只有当第一个nameserver 没有反应时才查询下面的nameserver.
domain 声明主机的域名。很多程序用到它，如邮件系统;当为没有域名的主机进行dns 查询时，也要用到。如果没有域名，主机名将被使，用删除所有在第一个点( . )前面的内容。
search 它的多个参数指明域名查询顺序。当要查询没有域名的主机，主机将在由search 声明的域中分别查找。
domain 和search 不能共存;如果同时存在，后面出现的将会被使用。
sortlist 允许将得到域名结果进行特定的排序。它的参数为网络/掩码对，允许任意的排列顺序。
再来使用nslookup工具来查询一下
[root@beiku1 named]# nslookup beiku1.sbyy.com Server: 10.138.130.161 Address: 10.138.130.161#53 Name: beiku1.sbyy.com Address: 10.138.130.161 [root@beiku1 named]# nslookup beiku2.sbyy.com Server: 10.138.130.161 Address: 10.138.130.161#53 Name: beiku2.sbyy.com Address: 10.138.130.162 [root@beiku1 named]# nslookup beikuscan.sbyy.com Server: 10.138.130.161 Address: 10.138.130.161#53 Name: beikuscan.sbyy.com Address: 10.138.130.169 Name: beikuscan.sbyy.com Address: 10.138.130.167 Name: beikuscan.sbyy.com Address: 10.138.130.168 [root@beiku1 named]# nslookup beiku1 Server: 10.138.130.161 Address: 10.138.130.161#53 Name: beiku1.sbyy.com Address: 10.138.130.161 [root@beiku1 named]# nslookup beiku2 Server: 10.138.130.161 Address: 10.138.130.161#53 Name: beiku2.sbyy.com Address: 10.138.130.162 [root@beiku1 named]# nslookup beikuscan Server: 10.138.130.161 Address: 10.138.130.161#53 Name: beikuscan.sbyy.com Address: 10.138.130.168 Name: beikuscan.sbyy.com Address: 10.138.130.169 Name: beikuscan.sbyy.com Address: 10.138.130.167 [root@beiku1 named]# nslookup 10.138.130.161 Server: 10.138.130.161 Address: 10.138.130.161#53 161.130.138.10.in-addr.arpa name = beiku1.sbyy.com. [root@beiku1 named]# nslookup 10.138.130.162 Server: 10.138.130.161 Address: 10.138.130.161#53 162.130.138.10.in-addr.arpa name = beiku2.sbyy.com. [root@beiku1 named]# nslookup 10.138.130.167 Server: 10.138.130.161 Address: 10.138.130.161#53 167.130.138.10.in-addr.arpa name = beikuscan.sbyy.com. [root@beiku1 named]# nslookup 10.138.130.168 Server: 10.138.130.161 Address: 10.138.130.161#53 168.130.138.10.in-addr.arpa name = beikuscan.sbyy.com. [root@beiku1 named]# nslookup 10.138.130.169 Server: 10.138.130.161 Address: 10.138.130.161#53 169.130.138.10.in-addr.arpa name = beikuscan.sbyy.com.
可以看到，DNS解析一切正常，上面只是配置了主DNS服务器，而且主DNS服务器也工作正常，现在我们来配置一个辅助DNS服务器
配置辅助DNS服务器
主DNS的东西和辅助DNS东西其实是相同的
一.安装软件包
[root@beiku2 soft]# rpm -qa | grep bind bind-chroot-9.3.6-4.P1.el5 kdebindings-3.5.4-6.el5 system-config-bind-4.0.3-4.el5 ypbind-1.19-12.el5 bind-libs-9.3.6-4.P1.el5 bind-9.3.6-4.P1.el5 bind-utils-9.3.6-4.P1.el5 [root@beiku2 soft]# rpm -ivh kdebindings-devel-3.5.4-6.el5.i386.rpm warning: kdebindings-devel-3.5.4-6.el5.i386.rpm: Header V3 DSA signature: NOKEY, key ID 37017186 Preparing... ########################################### [100%] 1:kdebindings-devel ########################################### [100%] [root@beiku2 soft]# rpm -ivh caching-nameserver-9.3.6-4.P1.el5.i386.rpm warning: caching-nameserver-9.3.6-4.P1.el5.i386.rpm: Header V3 DSA signature: NOKEY, key ID 37017186 Preparing... ########################################### [100%] 1:caching-nameserver ########################################### [100%] [root@beiku2 soft]# rpm -ivh bind-sdb-9.3.6-4.P1.el5.i386.rpm warning: bind-sdb-9.3.6-4.P1.el5.i386.rpm: Header V3 DSA signature: NOKEY, key ID 37017186 Preparing... ########################################### [100%] 1:bind-sdb ########################################### [100%] [root@beiku2 soft]# rpm -ivh bind-libbind-devel-9.3.6-4.P1.el5.i386.rpm warning: bind-libbind-devel-9.3.6-4.P1.el5.i386.rpm: Header V3 DSA signature: NOKEY, key ID 37017186 Preparing... ########################################### [100%] 1:bind-libbind-devel ########################################### [100%] [root@beiku2 soft]# rpm -ivh bind-devel-9.3.6-4.P1.el5.i386.rpm warning: bind-devel-9.3.6-4.P1.el5.i386.rpm: Header V3 DSA signature: NOKEY, key ID 37017186 Preparing... ########################################### [100%] 1:bind-devel ########################################### [100%]
二.复制模板文件
[root@beiku2 /]# cd /var/named/chroot/etc [root@beiku2 etc]# ls -lrt total 24 -rw-r--r-- 1 root root 3519 Feb 27 2006 localtime -rw-r----- 1 root named 955 Jul 30 2009 named.rfc1912.zones -rw-r----- 1 root named 1230 Jul 30 2009 named.caching-nameserver.conf -rw-r----- 1 root named 113 Nov 15 2014 rndc.key [root@beiku2 etc]# cp -p named.caching-nameserver.conf named.conf
三.编辑named.conf文件
[root@beiku2 etc]# vi named.conf
//
// named.caching-nameserver.conf
//
// Provided by Red Hat caching-nameserver package to configure the
// ISC BIND named(8) DNS server as a caching only nameserver
// (as a localhost DNS resolver only).
//
// See /usr/share/doc/bind*/sample/ for example named configuration files.
//
// DO NOT EDIT THIS FILE - use system-config-bind or an editor
// to create named.conf - edits to this file will be lost on
// caching-nameserver package upgrade.
//
options {
listen-on port 53 { any; };
listen-on-v6 port 53 { ::1; };
directory "/var/named";
dump-file "/var/named/data/cache_dump.db";
statistics-file "/var/named/data/named_stats.txt";
memstatistics-file "/var/named/data/named_mem_stats.txt";
// Those options should be used carefully because they disable port
// randomization
// query-source port 53;
// query-source-v6 port 53;
allow-query { 10.138.130.0/24; };
allow-query-cache { any; };
};
logging {
channel default_debug {
file "data/named.run";
severity dynamic;
};
};
view localhost_resolver {
match-clients { 10.138.130.0/24; };
match-destinations { any; };
recursion yes;
include "/etc/named.rfc1912.zones";
};
和主DNS配置一样
四.定义zone文件
[root@beiku2 etc]# vi named.rfc1912.zones
// named.rfc1912.zones:
//
// Provided by Red Hat caching-nameserver package
//
// ISC BIND named zone configuration for zones recommended by
// RFC 1912 section 4.1 : localhost TLDs and address zones
//
// See /usr/share/doc/bind*/sample/ for example named configuration files.
//
zone "sbyy.com" IN {
type slave;
masters {10.138.130.161;};
file "slaves/sbyy.com";
};
zone "0.138.10.in-addr.arpa" IN {
type slave;
masters {10.138.130.161;};
file "slaves/named.sbyy";
};
辅助DNS在定义zone文件的时候和主DNS有些不同
在辅助DNS里面 type要改为slave
master { 10.138.130.161; }; 而且必须指定主DNS的IP address
file “slaves/sbyy.com”;
file “slaves/named.sbyy”;
为什么要指定数据库文件在slaves目录下面呢,是因为slaves目录是拥有人和拥有组都是named用户，在启动DNS服务的时候，只有named有权限进行操作，所以我们要把数据库放在这个目录下面。
[root@beiku2 etc]# cd /var/named/chroot/var/named/ [root@beiku2 named]# ls -lrt total 44 drwxrwx--- 2 named named 4096 Jul 27 2004 slaves drwxrwx--- 2 named named 4096 Aug 26 2004 data -rw-r----- 1 root named 427 Jul 30 2009 named.zero -rw-r----- 1 root named 426 Jul 30 2009 named.local -rw-r----- 1 root named 424 Jul 30 2009 named.ip6.local -rw-r----- 1 root named 1892 Jul 30 2009 named.ca -rw-r----- 1 root named 427 Jul 30 2009 named.broadcast -rw-r----- 1 root named 195 Jul 30 2009 localhost.zone -rw-r----- 1 root named 198 Jul 30 2009 localdomain.zone [root@beiku2 named]# cd slaves [root@beiku2 slaves]# ls -lrt total 0
可以看到，slaves目录的拥有人和拥有组是named，并且现在的slaves目录下面是什么东西都没有的。
现在我们重启一下DNS服务
[root@beiku2 slaves]# service named restart Stopping named: [ OK ] Starting named: [ OK ]
可以看到，服务启动成功了。在启动服务的同时，我们来查看一下日志信息，看看日志里面有什么提示
[root@beiku2 slaves]# tail /var/log/messages Aug 25 23:41:49 beiku2 named[30421]: the working directory is not writable Aug 25 23:41:49 beiku2 named[30421]: running Aug 25 23:41:49 beiku2 named[30421]: zone 0.138.10.in-addr.arpa/IN/localhost_resolver: Transfer started. Aug 25 23:41:49 beiku2 named[30421]: transfer of '0.138.10.in-addr.arpa/IN' from 10.138.130.161#53: connected using 10.138.130.162#44647 Aug 25 23:41:49 beiku2 named[30421]: zone 0.138.10.in-addr.arpa/IN/localhost_resolver: transferred serial 1997022700 Aug 25 23:41:49 beiku2 named[30421]: transfer of '0.138.10.in-addr.arpa/IN' from 10.138.130.161#53: end of transfer Aug 25 23:41:49 beiku2 named[30421]: zone sbyy.com/IN/localhost_resolver: Transfer started. Aug 25 23:41:49 beiku2 named[30421]: transfer of 'sbyy.com/IN' from 10.138.130.161#53: connected using 10.138.130.162#56490 Aug 25 23:41:49 beiku2 named[30421]: zone sbyy.com/IN/localhost_resolver: transferred serial 42 Aug 25 23:41:49 beiku2 named[30421]: transfer of 'sbyy.com/IN' from 10.138.130.161#53: end of transfer
在日志里面可以看到，主DNS与辅助DNS正在同步序列号，同步成功，这个日志里面的信息非常的详细。
接下来，我们在到slaves目录下面去看看
[root@beiku2 slaves]# ls -lrt total 8 -rw-r--r-- 1 named named 414 Aug 25 23:41 sbyy.com -rw-r--r-- 1 named named 451 Aug 25 23:41 named.sbyy
刚才slaves目录下面的是什么东西都没有,现在就多了两个文件，example.com和named.example这个两个文件。这个就是我们刚才在定义zone文件的时候在slaves目录下面定义的，文件名是随意写的，这个没有关系，但是里面东西是和主DNS一样的。
我们查看这两个文件的具体内容
[root@beiku2 slaves]# cat sbyy.com
$ORIGIN .
$TTL 86400 ; 1 day
sbyy.com IN SOA sbyy.com. root.sbyy.com. (
42 ; serial
10800 ; refresh (3 hours)
900 ; retry (15 minutes)
604800 ; expire (1 week)
86400 ; minimum (1 day)
)
NS sbyy.com.
A 127.0.0.1
AAAA ::1
$ORIGIN sbyy.com.
beiku1 A 10.138.130.161
beikuscan1 A 10.138.130.167
beikuscan2 A 10.138.130.168
beikuscan3 A 10.138.130.169
beiku2 A 10.138.130.162
[root@beiku2 slaves]# cat named.sbyy
$ORIGIN .
$TTL 86400 ; 1 day
0.138.10.in-addr.arpa IN SOA localhost. root.localhost. (
1997022700 ; serial
28800 ; refresh (8 hours)
14400 ; retry (4 hours)
3600000 ; expire (5 weeks 6 days 16 hours)
86400 ; minimum (1 day)
)
NS localhost.
$ORIGIN 0.138.10.in-addr.arpa.
1 PTR localhost.
161 PTR beiku1.sbyy.com
167 PTR beikuscan1.sbyy.com
168 PTR beikuscan2.sbyy.com
169 PTR beikuscan3.sbyy.com
162 PTR beiku2.sbyy.com
这两个文件里面的内容和我们的主DNS的内容都是一样的。而且还帮我们整理的非常的漂亮。这些都是系统自动生成的。
现在我们来测试一下主DNS和辅助DNS可不可以正常的工作
[root@beiku2 slaves]# vi /etc/resolv.conf search sbyy.com nameserver 10.138.130.161 nameserver 10.138.130.162
现在我们将主DNS和辅助DNS都设置一下。然后在使用nslookup工具来测试
[root@beiku2 slaves]# nslooup beiku1 -bash: nslooup: command not found [root@beiku2 slaves]# nslookup beiku1 Server: 10.138.130.161 Address: 10.138.130.161#53 Name: beiku1.sbyy.com Address: 10.138.130.161 [root@beiku2 slaves]# nslookup beiku2 Server: 10.138.130.161 Address: 10.138.130.161#53 Name: beiku2.sbyy.com Address: 10.138.130.162
现在解析没有问题，还是有10.138.130.161这台主DNS来解析的。
接下来，我们将10.138.130.161这台主DNS给down，看下10.138.130.162这台辅助DNS能否正常工作。
[root@beiku1 named]# service named stop Stopping named: [ OK ]
用nslookup来测试一下
[root@beiku2 slaves]# nslookup beiku1 Server: 10.138.130.162 Address: 10.138.130.162#53 Name: beiku1.sbyy.com Address: 10.138.130.161
现在解析照样成功了，现在并不是通过10.138.130.161这台主DNS来解析出来的，而是通过我们的10.138.130.162这台辅助DNS来解析出来的。当我们网络中的主DNSdown掉的时候，我们的辅助DNS照样能够正常的工作。我们还可以实现负载均衡，可以在网络中的一半客户端的主DNS指向10.138.130.161，辅助DNS指向10.138.130.161。将网络中的另一半客户端的主DNS指向10.138.130.162，辅助DNS指向10.138.130.161。这样两台服务器都可以正常的工作，正常的为客户端解析，当其中的一台DNSdown掉后，另一台DNS也会继续的工作，这样就实现了简单的负载均衡。到目前为止，我们的主DNS Server 和我们的辅助DNS Server都已经设置成功了，并且都可以正常的工作了。
接下来，我们在做一个试验，我们在主DNS添加一条记录，看下辅助DNS能否检测试到这条记录，不能够在辅助DNS上面添加记录，这样没有意义，我们的主DNS是检测不到这条记录的。
[root@beiku1 named]# vi sbyy.zone
$TTL 86400
@ IN SOA @ root (
43 ; serial (d. adams)
2M ; refresh
2M ; retry
1W ; expiry
1D ) ; minimum
IN NS @
IN A 127.0.0.1
IN AAAA ::1
beiku1 IN A 10.138.130.161
beikuscan IN A 10.138.130.167
beikuscan IN A 10.138.130.168
beikuscan IN A 10.138.130.169
beiku2 IN A 10.138.130.162
www IN A 10.138.130.170
增加了www IN A 10.138.130.170记录。在主DNS里面做了新的操作以后，一定要将主DNS的序列号加一。否则辅助DNS是不会来同步我们的主DNS的。我们已经将主DNS的序列号加一了，但是默认情况下，主DNS与辅助DNS的同步时间是3H，这样我们很难看到效果，我们将它改为2M，然后在将重试时间改为2M，这样就代表每隔两分钟主DNS和辅助DNS进行同步，如果同步不成功，在隔两分钟同步一次。接下来我们将反向解析里面的也来修改一下
[root@beiku1 named]# vi named.sbyy
$TTL 86400
@ IN SOA beiku1.sbyy.com. root.sbyy.com. (
1997022703 ; Serial
120 ; Refresh
120 ; Retry
3600000 ; Expire
86400 ) ; Minimum
@ IN NS beiku1.sbyy.com.
167 IN PTR beikuscan.sbyy.com.
168 IN PTR beikuscan.sbyy.com.
169 IN PTR beikuscan.sbyy.com.
162 IN PTR beiku2.sbyy.com.
161 IN PTR beiku1.sbyy.com.
170 IN PTR www.sbyy.com.
这样，反向解析里面也已经修改完成了。现在将DNS服务重启
[root@beiku1 named]# service named restart Stopping named: [ OK ] Starting named: [ OK ]
重启成功，等几分钟之后在来看下效果。现在我们查看辅助DNS的正向解析数据库文件的内容
[root@beiku2 slaves]# cat sbyy.com
$ORIGIN .
$TTL 86400 ; 1 day
sbyy.com IN SOA beiku1.sbyy.com. root.sbyy.com. (
45 ; serial
120 ; refresh (2 minutes)
120 ; retry (2 minutes)
604800 ; expire (1 week)
86400 ; minimum (1 day)
)
NS beiku1.sbyy.com.
$ORIGIN sbyy.com.
beiku1 A 10.138.130.161
beiku2 A 10.138.130.162
beikuscan A 10.138.130.167
A 10.138.130.168
A 10.138.130.169
www A 10.138.130.170
OK，可以看到，我们刚才在主DNS里面添加的一条新的记录现在已经被辅助DNS同步过去了，而且辅助DNS的序列号和刷新时间，重试时间都同步了。下来我们查看辅助DNS的反向解析数据库文件的内容
[root@beiku2 slaves]# cat named.sbyy
RIGIN .
$TTL 86400 ; 1 day
0.138.10.in-addr.arpa IN SOA localhost. root.localhost. (
1997022702 ; serial
28800 ; refresh (8 hours)
14400 ; retry (4 hours)
3600000 ; expire (5 weeks 6 days 16 hours)
86400 ; minimum (1 day)
)
NS localhost.
$ORIGIN 0.138.10.in-addr.arpa.
1 PTR localhost.
161 PTR beiku1.sbyy.com
167 PTR beikuscan1.sbyy.com
168 PTR beikuscan2.sbyy.com
169 PTR beikuscan3.sbyy.com
162 PTR beiku2.sbyy.com
170 PTR www.sbyy.com
OK，也可以看到，辅助DNS也已经同步成功了，到此DNS的配置就完成了。
