简述使用BIND配置本地DNS服务器（centos 6.8）
DNS简介：
DNS，Domain Name System，域名系统，用于Internet上域名和IP地址的相互映射，使得用户不用记忆主机IP地址，仅通过与之对应的域名就可以访问该主机。
关于BIND软件：
https://www.isc.org/downloads/bind/
下面是本地dns服务器搭建过程，环境-centos6.8，本地IP-192.168.3.60。
1.yum安装bind和bind-utils，后者包含dns查询工具dig。
$ yum install bind bind-utils -y2.修改配置文件 named.conf
$ vim /etc/named.conf修改内容如下：
options {
//添加监听IP-192.168.3.60
listen-on port 53 { 127.0.0.1;192.168.3.60; };
};
//建立正向解析域（本地域）
zone "test.com" IN {
type master;
file "test.com.zone";
};
//建立反向解析域（本地域）
zone "3.168.192.in-addr.arpa" IN {
type master;
file "3.168.192.zone";
};检查配置语法正确与否：
$ named-checkconf3.创建区域文件
正向解析：
使用named.localhost文件的副本，更改属组为named。
$ cp named.localhost test.com.zone
$ chgrp named test.com.zone
$ vim test.com.zonetest.com.zone 内容如下：
$TTL 1D
@ IN SOA @ admin.test.com. (
2017020601 ; serial
1D ; refresh
1H ; retry
1W ; expire
3H ) ; minimum
NS ns.test.com.
MX 5 mail.test.com.
ns A 192.168.3.60
mail A 192.168.3.61
www A 192.168.3.62
bbs A 192.168.3.63检查语法正确与否：
$ named-checkzone "test.com" /var/named/test.com.zone 反向解析：
使用named.localhost文件的副本，更改属组为named。
$ cp named.localhost 3.168.192.zone
$ chgrp named 3.168.192.zone
$ vim 3.168.192.zone 3.168.192.zone 内容如下：
$TTL 1D
@ IN SOA @ admin.dt.com. (
2017020701 ; serial
1D ; refresh
1H ; retry
1W ; expire
3H ) ; minimum
IN NS ns.dt.com.
60 IN PTR ns.dt.com.
61 IN PTR mail.dt.com.
62 IN PTR www.dt.com.
63 IN PTR bbs.dt.com.检查语法正确与否：
$ named-checkzone "3.168.192.in-addr.arpa" /var/named/3.168.192.zone 4.启动named，测试dns解析
$ /etc/init.d/named start$ dig @192.168.3.60 bbs.test.com
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.47.rc1.el6_8.4 <<>> @192.168.3.60 bbs.test.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 16609
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 1
;; QUESTION SECTION:
;bbs.test.com. IN A
;; ANSWER SECTION:
bbs.test.com. 86400 IN A 192.168.3.62
;; AUTHORITY SECTION:
test.com. 86400 IN NS ns.test.com.
;; ADDITIONAL SECTION:
ns.test.com. 86400 IN A 192.168.3.60
;; Query time: 0 msec
;; SERVER: 192.168.3.60#53(192.168.3.60)
;; WHEN: Wed Feb 8 13:28:57 2017
;; MSG SIZE rcvd: 77遇到的问题和解决方法
1.修改完区域文件，重启named，出错：
$ /etc/init.d/named restart
Stopping named: [ OK ]
Starting named:
Error in named configuration:
dns_rdata_fromtext: test.com.zone:10: near 'mail.test.com.': not a valid number
zone test.com/IN: loading from master file test.com.zone failed: not a valid number
zone test.com/IN: not loaded due to errors.
_default/test.com/IN: not a valid number
zone 3.168.192.in-addr.arpa/IN: loaded serial 2017020701
zone localhost.localdomain/IN: loaded serial 0
zone localhost/IN: loaded serial 0
zone 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa/IN: loaded serial 0
zone 1.0.0.127.in-addr.arpa/IN: loaded serial 0
zone 0.in-addr.arpa/IN: loaded serial 0
[FAILED]
原因是正向解析区域文件中，MX记录缺少优先级，由“MX mail.test.com”改为“MX 5 mail.test.com”，不再报错。
2.使用named-checkzone检查区域文件，出错：
dns_rdata_fromtext: /var/named/test.com.zone:3: near '1D': not a valid number
zone test.com/IN: loading from master file /var/named/test.com.zone failed: not a valid number
zone test.com/IN: not loaded due to errors.解决方法：
在第2行” IN SOA “后、” ( “前，添加” @ “或” test.com. “，正确语句如下：
@ IN SOA @ admin.test.com. (
......@ IN SOA test.com. admin.test.com. (
......参考文章：
http://www.cnblogs.com/fengyutech/p/4917991.html
http://www.cnblogs.com/Kelly123/p/4225290.html
http://blog.csdn.net/hongweigg/article/details/7189175