第一章 简单模型实现
一、规划
二、环境准备
（一）DNS服务器
IP：172.16.23.135。这一台服务器被配置成为转发服务器，它负责解析为172.16.23.132和172.16.23.133两个地址，其它解析转发给网络服务提供商的DNS地址，这里选用114.114.114.114。
安装BIND，并配置。# yum -y install bind bind-utils
BIND的安装和配置，请看博主博文《DNS服务及基于BIND的实现》。
编辑主配置文件和区域文件
# vim /etc/named.conf// // named.conf//options { directory"/var/named";// recursion yes; forward only; forwarders { 114.114.114.114; };};zone "." IN { type hint; file "named.ca";};include "/etc/named.rfc1912.zones";# vim /etc/named.rfc1912.zoneszone "test.com" IN { type master;file "test.com.zfile";allow-update { 127.0.0.1; };allow-transfer { 127.0.0.1; };}; [root@localhost ~]# cd /var/named/[root@localhost named]# vim test.com.zfile[root@localhost named]# cat test.com.zfile $TTL 3600@ IN SOA ns1 webadmin ( 20140816011D1H1W3600) IN NS ns1 IN MX 10 mailns1 IN A 172.16.0.10 mail IN A 172.16.0.15www IN A 172.16.23.132 www IN A 172.16.23.133[root@localhost named]# named-checkzone "test.com" test.com.zfile zone test.com/IN: loaded serial 2014081601OK
启动服务开始测试
[root@localhost named]# dig -t A ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6_4.6 <<>> -t A ;; global options: +cmd;; Got answer:;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 36091;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0;; QUESTION SECTION: ;IN A;; ANSWER SECTION: 3418 IN CNAME test.blockdos.com.test.blockdos.com. 118 IN A 208.64.121.188;; Query time: 39 msec ;; SERVER: 172.16.0.1#53(172.16.0.1);; WHEN: Sat Aug 16 22:14:53 2014;; MSG SIZE rcvd: 74[root@localhost named]# dig -t A @127.0.0.1; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6_4.6 <<>> -t A @127.0.0.1 ;; global options: +cmd;; Got answer:;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 43764;; flags: qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 1, ADDITIONAL: 1;; QUESTION SECTION: ;IN A;; ANSWER SECTION: 3600 IN A 172.16.23.1323600 IN A 172.16.23.133;; AUTHORITY SECTION: test.com.3600 IN NS ns1.test.com.;; ADDITIONAL SECTION: ns1.test.com.3600 IN A 172.16.0.10;; Query time: 2 msec ;; SERVER: 127.0.0.1#53(127.0.0.1);; WHEN: Sat Aug 16 22:15:05 2014;; MSG SIZE rcvd: 96[root@localhost named]# dig -t A @127.0.0.1; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6_4.6 <<>> -t A @127.0.0.1 ;; global options: +cmd;; Got answer:;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 38708;; flags: qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 1, ADDITIONAL: 1;; QUESTION SECTION: ;IN A;; ANSWER SECTION: 3600 IN A 172.16.23.1333600 IN A 172.16.23.132;; AUTHORITY SECTION: test.com.3600 IN NS ns1.test.com.;; ADDITIONAL SECTION: ns1.test.com.3600 IN A 172.16.0.10;; Query time: 2 msec ;; SERVER: 127.0.0.1#53(127.0.0.1);; WHEN: Sat Aug 16 22:15:53 2014;; MSG SIZE rcvd: 96
说明：
可以看出，当指向DNS服务器172.16.23.135即本机的时候，返回aa即权威解答，同时注意解析的www服务器地址的顺序在变。
默认DNS工作在round-robin轮询模式。
可以考虑使用windows 的nslookup来查询
（二）WEB服务器1
关于WEB服务器的安装，请看博主博文《LAMP的几种简单实现及drupal、WordPress、phpMyAdmin部署》。这里不再赘述。
[root@localhost ~]# yum -y install httpd httpd-tools
默认站点根目录是/var/www/html
在其中增加页面index.html。
内容如下：
测试页Welcom to HTML World! 172.16.23.132
（三）WEB服务器2
方法同上，修改index.html的内容为
<h1>Welcom to HTML World! 172.16.23.133 </h1>
（四）NFS服务器
服务器端172.16.23.134
快忘了那些不高兴的事吧!你看就连今天的阳光都如此明媚灿烂，
