DNS的view設置【轉載】

 在實際的網絡應用中，咱們有時但願對於同一個Domain Name可以根據不一樣的請求IP

地址/區域，解析到不一樣的對應IP地址，好比：有時對於企業內部網絡和外部網絡但願對同一域名解析到不一樣的IP地址以達到安全目的或者應用目的，又好比爲了解決中國南北方電信/網通互訪速度差別問題，您也會但願電信用戶解析到的域名IP是位於電信網絡中的服務器，網通用戶亦然，使用戶可以訪問到臨近的最快的服務器。

    而這些應用均可以經過對DNS的簡單配置達到，使用DNS達到這一目的有如下的優勢：

l  低成本－無需添加任何專用設備，只需經過簡單配置便可； 

l  靈活性強－可隨時增長/刪除解析規則； 

l  有必定的可擴展能力－若是搭配Round Robin DNS可無縫快速的配置簡單的負載均衡；

    下面，咱們藉助Bind 9（Bind 8沒有這個功能哦）的這一特殊功能來實現域名的分離解析。在此例中，咱們繼續沿用x.centos.org做爲域名，讓局域網192.168.0.0/24內的機器除了192.168.0.40外都能解析到192.168.0.38，而192.168.0.40這臺機器只能解析到192.169.0.39這個地址。

首先，須要修改named.conf文件，對view 「internal」和view 「external」這兩個視圖區域進行分別設置。咱們將view 「localhost_resolver」這個視圖、key ddns key以及view視圖內的slave這個區域都註釋掉。而後，修改internal和external兩個視圖。

//

// Sample named.conf BIND DNS server 'named' configuration file

// for the Red Hat BIND distribution.

//

// See the BIND Administrator's Reference Manual (ARM) for details, in:

//   file:///usr/share/doc/bind-*/arm/Bv9ARM.html

// Also see the BIND Configuration GUI : /usr/bin/system-config-bind and

// its manual.

//

options                

{

    // Those options should be used carefully because they disable port

    // randomization

           query-source    port 53;            

         // query-source-v6 port 53;     

        

         // Put files that named is allowed to write in the data/ directory:

         directory "/var/named"; // the default     

         dump-file                  "data/cache_dump.db"; 

        statistics-file  "data/named_stats.txt"; 

        memstatistics-file  "data/named_mem_stats.txt";

};

logging                

{

/*      If you want to enable debugging, eg. using the 'rndc trace' command,

 *      named will try to write the 'named.run' file in the $directory (/var/named).

 *      By default, SELinux policy does not allow named to modify the /var/named directory,

 *      so put the default debug log file in data/ :

 */

        channel default_debug {

                file "data/named.run";

                severity dynamic;

        };      

};

//

// All BIND 9 zones are in a "view", which allow different zones to be served

// to different types of client addresses, and for options to be set for groups

// of zones.

//

// By default, if named.conf contains no "view" clauses, all zones are in the

// "default" view, which matches all clients.

//

// If named.conf contains any "view" clause, then all zones MUST be in a view;

// so it is recommended to start off using views to avoid having to restructure

// your configuration files in the future.

//

#view "localhost_resolver"     

#{

/* This view sets up named to be a localhost resolver ( caching only nameserver ).

 * If all you want is a caching-only nameserver, then you need only define this view:

 */

#       match-clients                   { localhost; };     

#       match-destinations        { localhost; };    

#       recursion yes;                   

         # all views must contain the root hints zone:

#       include "/etc/named.root.hints";

 

        /* these are zones that contain definitions for all the localhost

         * names and addresses, as recommended in RFC1912 - these names should

          * ONLY be served to localhost clients:

          */

#       include "/etc/named.rfc1912.zones";

#};

view "internal"          

{

/* This view will contain zones you want to serve only to "internal" clients

   that connect via your directly attached LAN interfaces - "localnets" .

 */

         match-clients           { 192.168.0.40; };  //設置internal區域由192.168.0.40這個地址解析。

#       match-destinations        { localnets; };

         recursion yes;

         // all views must contain the root hints zone:

         include "/etc/named.root.hints";

 

    include "/etc/named.rfc1912.zones";  //將internal視圖的區域定義文件包含進來。

         // you should not serve your rfc1912 names to non-localhost clients.

 

         // These are your "authoritative" internal zones, and would probably

         // also be included in the "localhost_resolver" view above :

 

         zone "my.internal.zone" {                 

                   type master;

                   file "my.internal.zone.db";

         };

#       zone "my.slave.internal.zone" {            

#                type slave;

#                file "slaves/my.slave.internal.zone.db";

#                masters { /* put master nameserver IPs here */ 127.0.0.1; } ;

                   // put slave zones in the slaves/ directory so named can update them

#       };     

#       zone "my.ddns.internal.zone" {          

#                type master;

#                allow-update { key ddns_key; };

#                file "slaves/my.ddns.internal.zone.db";

                   // put dynamically updateable zones in the slaves/ directory so named can update them

#       };                        

};

#key ddns_key  

#{

#       algorithm hmac-md5;

#       secret "use /usr/sbin/dns-keygen to generate TSIG keys";

#};

view    "external"                   

{

/* This view will contain zones you want to serve only to "external" clients

 * that have addresses that are not on your directly attached LAN interface subnets:

 */

         match-clients           { !192.168.0.40;192.168.0.0/24;  }; //設置external視圖由192.168.0.0

這個網段的機器解析，但

192.168.0.40這臺主機不能解析。

#       match-destinations        { any; };

 

         recursion no;

         // you'd probably want to deny recursion to external clients, so you don't

        // end up providing free DNS service to all takers

 

         // all views must contain the root hints zone:

         include "/etc/named.root.hints";

    include 「/etc/named.other.zones」;   //添加external的區域定義文件，文件名隨意。

         // These are your "authoritative" external zones, and would probably

        // contain entries for just your web and mail servers:

 

         zone "my.external.zone" {

                   type master;

                   file "my.external.zone.db";

         };

};

接下來，修改internal和external視圖的區域定義文件。首先，修改internal區域定義文件named.rfc1912.zones，根據須要添加正向和反響解析區域。

zone "centos.org" IN {        

         type master;           

         file "centos.org.zone";    

         allow-update { none; };  

};

 

zone "0.168.192.in-addr.arpa" IN { 

         type master;              

         file "0.168.192.zone";        

         allow-update { none; };

};

下面，將named.rfc1912.zones文件複製一份，並改名爲named.other.zones（這個文件名要和named.conf裏相應視圖內的文件定義要一致哦！）。而後，對named.other.zones文件進行修改。

zone "centos.org" IN {        

         type master;           

         file "centos.org1.zone";    //這裏修改external的正向解析文件爲centos.org1.zone。

         allow-update { none; };  

};

 

zone "0.168.192.in-addr.arpa" IN { 

         type master;              

         file "0.168.1921.zone";     //這裏修改external的反向解析文件爲0.168.1921.zone。

         allow-update { none; };

};

下面，對區域定義中定義的文件進行配置。下面是internal的區域解析文件：

$TTL          86400                                    

@              IN SOA      x.centos.org.  root.x.centos.org. (

                                     2009101901     ; serial (d. adams)  

                                               3H             ; refresh         

                                               15M          ; retry          

                                               1W            ; expiry          

                                               1D )           ; minimum      

                 IN NS                  x.centos.org.         

            IN MX       mail.centos.org.       

X                IN A               192.168.0.39        

www        IN CNAME   x.centos.org.   //此爲正向解析文件

———————————————————————————————————————

$TTL          86400                                    

@              IN SOA      x.centos.org.  root.x.centos.org. (

                                     2009101901     ; serial (d. adams)  

                                               3H             ; refresh          

                                               15M          ; retry           

                                               1W            ; expiry         

                                               1D )           ; minimum      

                 IN NS                  x.centos.org.  

39          IN PTR       x.centos.org.   //此爲逆向解析文件

這裏，internal的正向解析文件爲centos.org.zone，逆向解析文件爲0.168.192.zone；external的正向解析文件爲centos.org1.zone，逆向解析文件爲0.168.1921.zone。兩個視圖的解析文件配置方法同樣，只是IP地址不一樣。能夠先將internal的解析文件配置好，而後複製一份並改名，而後稍做修改便可。

一切修改完畢後，重啓DNS服務器，而後進行測試便可。