如何搭建智能DNS
这篇文章给大家分享的是有关如何搭建智能DNS的内容。小编觉得挺实用的，因此分享给大家做个参考，一起跟随小编过来看看吧。
智能DNS搭建方案
智能DNS主要通过用户源IP来判断来源，然后根据不同的策略解析到不同的IP地址来实现。使得用户可以就近访问所需的资源，提高访问速度，提升用户感知。
智能DNS可通过bind的view功能来实现。
BIND的VIEW功能配置如下：
软件版本：bind-9.9.5-P1.tar.gz
依赖：gcc
openssl-0.9.8zb.tar.gz（bind的DNSSEC需要）
1. 安装openssl
tar xf openssl-0.9.8zb.tar.gz
cd openssl-0.9.8zb
./config --prefix=/usr/local --openssldir=/usr/local/openssl && make && make install
2. 安装bind
tar xf bind-9.9.5-P1.tar.gz
cd bind-9.9.5-P1
./configure --prefix=/home/bind --enable-threads --with-openssl=/usr/local/openssl
make && make install
3. 配置bind
由于要配置view，那么所有的zone文件都必须放在view里面，所以做如下配置：注释掉named.conf中的named.conf.zone和named.rfc1912.zones
vi /home/bind/etc/named.conf
#named.conf file
include "/home/bind/etc/named.conf.options";
include "/home/bind/etc/named.conf.acl";
include "/home/bind/etc/named.conf.controls";
include "/home/bind/etc/named.conf.server";
include "/home/bind/etc/named.conf.key";
include "/home/bind/etc/named.conf.dlz";
include "/home/bind/etc/named.conf.trusted-keys";
include "/home/bind/etc/named.conf.view";
#include "/home/bind/etc/named.conf.zone";
#include "/home/bind/etc/named.rfc1912.zones";
配置view
vi /home/bind/etc/named.conf.view
view "ctc_view_zone" {
match-clients { CTC; };
include "/home/bind/var/named/view_zone/ctc_zone";
};
view "cuc_view_zone" {
match-clients { CUC; };
include "/home/bind/var/named/view_zone/cuc_zone";
};
view "cmc_view_zone" {
match-clients { CMC; };
include "/home/bind/var/named/view_zone/cmc_zone";
};
view "any_view_zone" {
match-clients { any; };
include "/home/bind/var/named/view_zone/any_zone";
};
分别为电信、联通、移动配置view，match-clients对应各自的ACL，实现筛选，include对应各自的zone配置文件。最后一条view为默认的view，view的匹配顺序是从上往下的，所以默认的view配置在最后。
配置zone文件
在/home/bind/var/named/view_zone下创建各自对应的zone文件
ls-l /home/bind/var/named/view_zone
total 16
-rw-r--r--. 1 root root 175 Aug 12 17:47 any_zone
-rw-r--r--. 1 root root 175 Aug 13 17:22 cmc_zone
-rw-r--r--. 1 root root 175 Aug 12 17:47 ctc_zone
-rw-r--r--. 1 root root 175 Aug 12 18:18 cuc_zone
vi /home/bind/var/named/view_zone/ctc_zone
zone "." IN {
type hint;
file "/home/bind/var/named/named.ca";
};
zone "test.com" IN {
type master;
file "/home/bind/var/named/ctc/test.com";
allow-update { none; };
};
Vi /home/bind/var/named/view_zone/cuc_zone
zone "." IN {
type hint;
file "/home/bind/var/named/named.ca";
};
zone "test.com" IN {
type master;
file "/home/bind/var/named/cuc/test.com";
allow-update { none; };
};
Vi /home/bind/var/named/view_zone/cmc_zone
zone "." IN {
type hint;
file "/home/bind/var/named/named.ca";
};
zone "test.com" IN {
type master;
file "/home/bind/var/named/cmc/test.com";
allow-update { none; };
};
vi /home/bind/var/named/view_zone/any_zone
zone "." IN {
type hint;
file "/home/bind/var/named/named.ca";
};
zone "test.com" IN {
type master;
file "/home/bind/var/named/any/test.com";
allow-update { none; };
};
在对应的目录下配置zone数据文件,配置一条A记录便于测试
vi /home/bind/var/named/ctc/test.com
$TTL 86400
@ IN SOA test.com. root.localhost. (
42 ; serial (d. adams)
3H ; refresh
15M ; retry
1W ; expiry
1D ) ; minimum
IN NS ns
ns IN A 115.182.75.10
www IN A 1.1.1.1
vi /home/bind/var/named/cuc/test.com
$TTL 86400
@ IN SOA test.com. root.localhost. (
42 ; serial (d. adams)
3H ; refresh
15M ; retry
1W ; expiry
1D ) ; minimum
IN NS ns
ns IN A 115.182.75.10
www IN A 2.2.2.2
vi /home/bind/var/named/cmc/test.com
$TTL 86400
@ IN SOA test.com. root.localhost. (
42 ; serial (d. adams)
3H ; refresh
15M ; retry
1W ; expiry
1D ) ; minimum
IN NS ns
ns IN A 115.182.75.10
www IN A 3.3.3.3
vi /home/bind/var/named/any/test.com
$TTL 86400
@ IN SOA test.com. root.localhost. (
42 ; serial (d. adams)
3H ; refresh
15M ; retry
1W ; expiry
1D ) ; minimum
IN NS ns
ns IN A 115.182.75.10
www IN A 4.4.4.4
配置ACL
由于IP条目数较多，所以另外创建ACL的文件方便管理
首先在named.conf中关联相应的文件
vi /home/bind/etc/named.conf
#named.conf file
include "/home/bind/etc/named.conf.options";
include "/home/bind/etc/named.conf.acl";
include "/home/bind/etc/named.conf.controls";
include "/home/bind/etc/named.conf.server";
include "/home/bind/etc/named.conf.key";
include "/home/bind/etc/named.conf.dlz";
include "/home/bind/etc/named.conf.trusted-keys";
include "/home/bind/etc/named.conf.view";
#include "/home/bind/etc/named.conf.zone";
#include "/home/bind/etc/named.rfc1912.zones";
include "/home/bind/etc/named.conf.log";
include "/home/bind/etc/ACL/dianxinACL";
include "/home/bind/etc/ACL/yidongACL";
include "/home/bind/etc/ACL/liantongACL";
include "/home/bind/etc/ACL/changkuanACL";
include "/home/bind/etc/ACL/tietongACL";
include "/home/bind/etc/ACL/jiaoyukeyanACL";
每个文件对应相应的IP地址库
格式为：acl "acl_name" { xx.xx.xx.xx; }; 如下所示：
vi /home/bind/etc/ACL/yidongACL
acl "CMC" {
36.128.0.0/10;
39.128.0.0/10;
111.0.0.0/10;
112.0.0.0/10;
……
221.176.0.0/13;
223.64.0.0/10;
};
至此bind的view已经配置完成
启动bind
/home/bind/sbin/named -u root -c /home/bind/etc/named.conf
(最好创建一个bind账号来启动，chown -R bind:bind /home/bind)
ps -ef | grep named 查看服务是否启动
使用/home/bind/sbin/named -u root -c /home/bind/etc/named.conf -g可以查看启动过程，方便排错
测试时，会根据源IP判断来源，然后解析到指定的地址，如下：
域名 电信用户解析IP 联通用户解析IP 移动用户解析IP 其他用户解析IP
www.test.com 1.1.1.1 2.2.2.2 3.3.3.3 4.4.4.4
解析命令
dig @115.182.75.10 www.test.com A
nslookup www.test.com 115.182.75.10
host -t A www.test.com 115.182.75.10
附上一个bind自带的压力测试工具queryperf
在解压 bind-9.9.5-P1.tar.gz后，在解压的文件中有个queryperf的目录，具体路径为：bind-9.9.5-P1/contrib/queryperf
在queryperf目录下执行：sh configure && make
之后会生成一个queryperf执行文件
基本用法如下：
./queryperf -d domain-file -s 8.8.8.8 -l 60 -T100
-d 后接一个域名列表文件，一行一个域名，格式为:domain type
www.163.com A
qq.com MX
www.baidu.com CNAME
www.test.com NS
-s 后接测试使用的DNS服务器IP
-l 测试时间，单位为秒
-T 每秒发送的请求数（qps）
命令执行完成后会输出结果，如下：
Statistics:
Parse input file: multiple times
Run time limit: 60 seconds
Ran through file: 5999 times
Queries sent: 6000 queries #查询总请求数
Queries completed: 6000 queries #查询成功的请求数
Queries lost: 0 queries #查询失败的请求数
Queries delayed(?): 0 queries
RTT max: 0.000520 sec
RTT min: 0.000109 sec
RTT average: 0.000291 sec
RTT std deviation: 0.000062 sec
RTT out of range: 0 queries
Percentage completed: 100.00%
Percentage lost: 0.00%
Started at: Fri Aug 15 10:42:00 2014
Finished at: Fri Aug 15 10:43:00 2014
Ran for: 60.000338 seconds
Queries per second: 99.999437 qps #每秒查询的次数（qps）
Total QPS/target: 99.999437/100 qps
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