利用dnsmasq来修改dns记录
我想做技术的或多或少都会知道dnsmasq，因为基本上所有的家用路由都内置了它，使用他来做域名服务的缓存代理。
仔细研究你会发现，除了缓存代理的基本功能之外，它修改dns记录的功能也很有意思。看看下面：
1. 安装dnsmasq:
在centos linux上的，可以直接yum安装：
yum install -y dnsmasq
2. 配置dnsmasq:
vim /etc/dnsmasq.conf
#监听所有网卡
bind-interfaces
#修改A记录
address=/www.163.com/1.2.3.4
#修改mx记录
mx-host=126.com,m.126.com,10
mx-host=163.com,m.163.com,10
保存配置文件，重启dnsmasq:
[root@oracle ~]# service dnsmasq restart
Shutting down dnsmasq: [ OK ]
Starting dnsmasq: [ OK ]
3. 用dig查询一下结果
[root@oracle ~]# dig @127.0.0.1 www.163.com
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6_4.6 <<>> @127.0.0.1 www.163.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 56629
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;www.163.com. IN A
;; ANSWER SECTION:
www.163.com. 0 IN A 1.2.3.4
;; Query time: 0 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Mon Aug 11 22:25:17 2014
;; MSG SIZE rcvd: 45
[root@oracle ~]# dig @127.0.0.1 163.com mx
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6_4.6 <<>> @127.0.0.1 163.com mx
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4324
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;163.com. IN MX
;; ANSWER SECTION:
163.com. 0 IN MX 10 m.163.com.
;; Query time: 0 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Mon Aug 11 22:25:21 2014
;; MSG SIZE rcvd: 50
[root@oracle ~]# dig @127.0.0.1 126.com mx
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6_4.6 <<>> @127.0.0.1 126.com mx
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 50441
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;126.com. IN MX
;; ANSWER SECTION:
126.com. 0 IN MX 10 m.126.com.
;; Query time: 0 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Mon Aug 11 22:25:25 2014
;; MSG SIZE rcvd: 50
[root@oracle ~]# dig @127.0.0.1 sina.com.cn mx
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6_4.6 <<>> @127.0.0.1 sina.com.cn mx
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 34068
;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;sina.com.cn. IN MX
;; ANSWER SECTION:
sina.com.cn. 181 IN MX 10 freemx2.sinamail.sina.com.cn.
sina.com.cn. 181 IN MX 5 freemx.sinamail.sina.com.cn.
sina.com.cn. 181 IN MX 10 freemx1.sinamail.sina.com.cn.
sina.com.cn. 181 IN MX 10 freemx3.sinamail.sina.com.cn.
;; Query time: 6 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Mon Aug 11 22:25:40 2014
;; MSG SIZE rcvd: 133
至于这个功能有什么用处?不用我说了，你懂的。。。
