如何轻松应对DNS劫持

如何判断所用的dns 有没有受到劫持,最简单的测试办法:用nslookup 去查询一个不存在的域名,如果返回一个IP,通过浏览打开这个IP会发现是一个广告页,那么这个DNS 已经被劫持了,如果返回** server can't find wwwsfsefse.com: NXDOMAIN  则未被劫持。

例:

未被劫持的DNS:

[root@mail ~]# nslookup serwr3rsf.com 61.235.70.98
Server:         61.235.70.98
Address:        61.235.70.98#53
** server can't find serwr3rsf.com: NXDOMAIN

已经被劫持的DNS:

# nslookup sfsef333sf.com  202.96.128.86
Server:         202.96.128.86
Address:        202.96.128.86#53
Non-authoritative answer:
Name:   sfsef333sf.com
Address: 61.140.3.66
[root@localhost ~]# yum install caching-nameserver

[root@localhost ~]# chkconfig named on

[root@localhost ~]# service named start

Starting named:                                            [  OK  ]

编辑/etc/resolv.conf,改为下面的内容:

nameserver 127.0.0.1

测试:

[root@localhost ~]# nslookup www.google.com
Server:         127.0.0.1
Address:        127.0.0.1#53
Non-authoritative answer:
www.google.com  canonical name = www.l.google.com.
Name:   www.l.google.com
Address: 64.233.189.99
Name:   www.l.google.com
Address: 64.233.189.103
Name:   www.l.google.com
Address: 64.233.189.104
Name:   www.l.google.com
Address: 64.233.189.147
[root@localhost ~]# nslookup sefsf2sfef.com
Server:         127.0.0.1
Address:        127.0.0.1#53
** server can't find sefsf2sfef.com: NXDOMAIN

测试成功!

 

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