标签：code loaded resolve rect multicast libs disco flags question
前提准备：
一台centos7做服务器，两张网卡（桥接and仅主机），一台centos6做客户端，仅主机
##### A、搭建DNS服务器：
1、[root@centos7 ~]# yum install bind
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
Resolving Dependencies
Installed:
bind.x86_64 32:9.9.4-72.el7
Dependency Installed:
python-ply.noarch 0:3.4-11.el7
Complete!
2、[root@centos7 ~]# rpm -ql bind
/etc/logrotate.d/named
/etc/named
/etc/named.conf
/etc/named.iscdlv.key
/etc/named.rfc1912.zones
/etc/named.root.key
/etc/rndc.conf
/etc/rndc.key
/etc/rwtab.d/named
/etc/sysconfig/named
/run/named
/var/log/named.log
/var/named
/var/named/data
/var/named/dynamic
/var/named/named.ca
/var/named/named.empty
/var/named/named.localhost
/var/named/named.loopback
/var/named/slaves
3、[root@centos7 ~]# rpm -qa "bind*"
bind-libs-lite-9.9.4-72.el7.x86_64
bind-license-9.9.4-72.el7.noarch
bind-9.9.4-72.el7.x86_64
bind-libs-9.9.4-72.el7.x86_64
bind-utils-9.9.4-72.el7.x86_64
4、数据库存放于 /var/named 下 ，且系统默认named已安装，
5、查看named的状态且启动该服务：
[root@centos7 ~]# systemctl status named
● named.service - Berkeley Internet Name Domain (DNS)
Loaded: loaded (/usr/lib/systemd/system/named.service; disabled; vendor preset: disabled)
Active: inactive (dead)
[root@centos7 ~]# systemctl start named
[root@centos7 ~]#
6、查看IP，有IP即可上网
[root@centos7 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:87:73:17 brd ff:ff:ff:ff:ff:ff
inet 192.168.58.254/24 brd 192.168.58.255 scope global noprefixroute ens33
valid_lft forever preferred_lft forever
inet6 fe80::20c:29ff:fe87:7317/64 scope link
valid_lft forever preferred_lft forever
3: ens37: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:87:73:21 brd ff:ff:ff:ff:ff:ff
inet 172.20.119.243/16 brd 172.20.255.255 scope global noprefixroute dynamic ens37
valid_lft 83928sec preferred_lft 83928sec
inet6 fe80::23ec:ee7:326a:3f9c/64 scope link noprefixroute
valid_lft forever preferred_lft forever
7、编辑网卡配置文件,添加DNS1=192.168.58.254：
[root@Centos6 ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth0
[root@Centos6 ~]# service network restart
Shutting down interface eth0: Device state: 3 (disconnected)
[ OK ]
Shutting down loopback interface: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: Active connection state: activating
Active connection path: /org/freedesktop/NetworkManager/ActiveConnection/6
state: activated
Connection activated
[ OK ]
8、我们在客户端查看配置文件，会显示主机IP：
[root@Centos6 ~]# cat /etc/resolv.conf
domain localdomain
search localdomain
nameserver 192.168.58.1
nameserver 192.168.58.254
9、[root@Centos6 ~]# host www.qq.com
;; connection timed out; trying next origin
;; connection timed out; no servers could be reached
此时，我们去修改配置文件：
10、[root@centos7 ~]# vim /etc/named.conf
//
// 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.
//
// See the BIND Administrator‘s Reference Manual (ARM) for details about the
// configuration located in /usr/share/doc/bind-{version}/Bv9ARM.html
options {
listen-on port 53 { localhost; };
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";
recursing-file "/var/named/data/named.recursing";
secroots-file "/var/named/data/named.secroots";
allow-query { any; };
/*
- 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 "/etc/named.conf" 61L, 1802C
11、使其生效：
[root@centos7 ~]# rndc reload
server reload successful
12、此时作为客户端，去访问百度，能通，如下：
[root@Centos6 ~]# dig www.baidu.com
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.68.rc1.el6 <<>> www.baidu.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 60669
;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 5, ADDITIONAL: 5
;; QUESTION SECTION:
;www.baidu.com. IN A
;; ANSWER SECTION:
www.baidu.com. 1200 IN CNAME www.a.shifen.com.
www.a.shifen.com. 300 IN A 61.135.169.125
www.a.shifen.com. 300 IN A 61.135.169.121
;; AUTHORITY SECTION:
a.shifen.com. 1200 IN NS ns4.a.shifen.com.
a.shifen.com. 1200 IN NS ns1.a.shifen.com.
a.shifen.com. 1200 IN NS ns2.a.shifen.com.
a.shifen.com. 1200 IN NS ns5.a.shifen.com.
a.shifen.com. 1200 IN NS ns3.a.shifen.com.
;; ADDITIONAL SECTION:
ns5.a.shifen.com. 1200 IN A 180.76.76.95
ns1.a.shifen.com. 1200 IN A 61.135.165.224
ns3.a.shifen.com. 1200 IN A 112.80.255.253
ns2.a.shifen.com. 1200 IN A 220.181.57.142
ns4.a.shifen.com. 1200 IN A 14.215.177.229
;; Query time: 1018 msec
;; SERVER: 192.168.58.254#53(192.168.58.254)
;; WHEN: Thu Jan 31 19:09:55 2019
;; MSG SIZE rcvd: 260分析：此时作为客户端尽管无上外网功能，去ping百度可通，当把7的内网关闭，6无法访问外网，却可以访问7访问过的百度，这是7留下了缓存！当把7的缓存rndc flush 清除掉，6就无法再访问外网了，所以，7就叫只缓存服务器，只利用缓存去访问。
[root@centos7 ~]# vim /etc/named.conf
其中的 “ include "/etc/named.rfc1912.zones"; ” 专门存放域名的
查看：[root@centos7 ~]# vim /etc/named.rfc1912.zones
zone "localhost.localdomain" IN {
type master;
file "named.localhost";
allow-update { none; };
};
zone "localhost" IN {
type master;
file "named.localhost";
allow-update { none; };
};
zone "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa" IN {
type master;
file "named.loopback";
allow-update { none; };
};
zone "1.0.0.127.in-addr.arpa" IN {
type master;
file "named.loopback";
allow-update { none; };
};
zone "0.in-addr.arpa" IN {
type master;
file "named.empty";
allow-update { none; };
};
type master;
file "magedu.com.zones";}; 添加进去
[root@centos7 ~]# named-checkconf 来检查语法，无错不提示
[root@centos7 named]# ls
data dynamic named.ca named.empty named.localhost named.loopback slaves
[root@centos7 named]# cp -p named.localhost magedu.com.zone
[root@centos7 named]# id named
uid=25(named) gid=25(named) groups=25(named)
[root@centos7 named]# vim magedu.com.zone
$TTL 1D
@ IN SOA @ rname.invalid. (
0 ; serial
1D ; refresh
1H ; retry
1W ; expire
3H ) ; minimum
NS @
A 127.0.0.1
AAAA :
"magedu.com.zone" 10L, 152C
我们将其文件修改，变成下图所示：$TTL 1D
@ IN SOA master admin.magedu.com. (
2019013120 ; serial
1D ; refresh
1H ; retry
1W ; expire
3H ) ; minimun
NS master
master A 192.168.58.254
www CNAME websrv
websrv A 192.168.58.133
blog A 192.168.58.136
@ mx 10 mailsrv1
@ mx 20 mailsrv2
mailsrv1 A 192.168.58.137
mailsrv2 A 192.168.58.138
使用“ named-checkzone ” 来检查语法。
[root@centos7 ~]# rndc reload
server reload successful
[root@Centos6 ~]# cat /etc/resolv.conf
domain localdomain
nameserver 192.168.58.254
搜索结果如下：
[root@Centos6 ~]# dig www.magedu.com
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.68.rc1.el6 <<>> www.magedu.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 15911
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 18
;; QUESTION SECTION:
;www.magedu.com. IN A
;; ANSWER SECTION:
www.magedu.com. 600 IN A 101.200.188.230
;; AUTHORITY SECTION:
magedu.com. 172154 IN NS ns2.alidns.com.
magedu.com. 172154 IN NS ns1.alidns.com.
我们现在恢复网卡：ifconfig Eth1 up
再添加一个路由：
route add default gw 192.168.58.100 (可随便写)
ping www.baidu.com 可通但IP每次都不一样，
说明DNS服务可以做到均衡负载的功能。
标签：code loaded resolve rect multicast libs disco flags question
原文地址：http://blog.51cto.com/14128387/2348284
