Centos 搭建named dns服務沒法解析外網地址

搭建了DNS服務器來解析自定義的域名，可是在遇到非自定義的域名時，不會去自動解析。使用nslookup 會提示 ** server can't find xxxx: NXDOMAIN

網上找了說要配置DNS轉發，在/etc/named.conf中配置 forward 和 forwarders，可是配完之後，確沒有和想象的同樣，自動拿到轉發的服務器解析。最後快要奔潰時，看到論壇裏有說把key相關的都註釋掉，而後蠻試一下，竟然能夠了。只須要註釋如下這行。

完整的配置文件以下：

//
// named.conf
//
// Provided by Red Hat bind package to configure the ISC BIND named(8) DNS
// server as a caching only nameserver (as a localhost DNS resolver only).
//
// See /usr/share/doc/bind*/sample/ for example named configuration files.
//

options {
        //listen-on port 53 { 127.0.0.1; };
        listen-on port 53 { 127.0.0.1;192.168.200.100; };
        //listen-on-v6 port 53 { ::1; };
        directory       "/var/named";
        dump-file       "/var/named/data/cache_dump.db";
        statistics-file "/var/named/data/named_stats.txt";
        memstatistics-file "/var/named/data/named_mem_stats.txt";
        //allow-query     { localhost; };
        allow-query     { any; };
        //allow-transfer { 202.106.0.20; };
        //allow-recursion       { 202.106.0.20; };
        forward         first;
        forwarders      { 219.141.140.10; };
        //forward               only;

        /* 
         - If you are building an AUTHORITATIVE DNS server, do NOT enable recursion.
         - If you are building a RECURSIVE (caching) DNS server, you need to enable 
           recursion. 
         - If your recursive DNS server has a public IP address, you MUST enable access 
           control to limit queries to your legitimate users. Failing to do so will
           cause your server to become part of large scale DNS amplification 
           attacks. Implementing BCP38 within your network would greatly
           reduce such attack surface 
        */
        recursion yes;

        dnssec-enable yes;
        dnssec-validation yes;
        dnssec-lookaside auto;

        /* Path to ISC DLV key */
        bindkeys-file "/etc/named.iscdlv.key";

        managed-keys-directory "/var/named/dynamic";

        pid-file "/run/named/named.pid";
        session-keyfile "/run/named/session.key";
};

logging {
        channel default_debug {
                file "data/named.run";
                severity dynamic;
        };
};

zone "." IN {
        type hint;
        file "named.ca";
};

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

當你配置的有主從dns服務器的時候，在主DNS宕機的時候，須要在內網機器中配置以下參數，否則你全部的服務器訪問外網API的時候會超時，致使沒法解析：

[root@dev ~]# cat /etc/resolv.conf 
options timeout:1 attempts:1 rotate
nameserver 10.143.22.118
nameserver 10.143.22.116