Oracle Linux 7.1配置DNS服务
一.安装DNS需要的软件包
# yum install bind-libs bind bind-utils
二.编辑named.conf文件
在编辑前先复制一份named.conf文件
[root@jytest1 ~]# cp /etc/named.conf /etc/named.conf.backup
[root@jytest1 ~]# vi /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.
//
options {
listen-on port 53 { any; };--将127.0.0.1修改成any
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 { any; };--将127.0.0.1修改成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
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";
三.配置host.conf
[root@jytest1 ~]# cat /etc/host.conf multi on
该文件指定如何解析主机名。Linux通过解析器库来获得主机名对应的IP地址。下面是一个“/etc/host.conf”的示例：
order bind,hosts
multi on
nospoof on
“order bind,hosts”指定主机名查询顺序，这里规定先使用DNS来解析域名，然后再查询“/etc/hosts”文件(也可以相反)。
“multi on”指定是否“/etc/hosts”文件中指定的主机可以有多个地址，拥有多个IP地址的主机一般称为多穴主机。
“nospoof on”指不允许对该服务器进行IP地址欺骗。IP欺骗是一种攻击系统安全的手段，通过把IP地址伪装成别的计算机，来取得其它计算机的信任。
四.修改/etc/named.rfc1912.zones
[root@jytest1 ~]# cp /etc/named.rfc1912.zones /etc/named.rfc1912.zones.backup
[root@jytest1 ~]# vi /etc/named.rfc1912.zones
// named.rfc1912.zones:
//
// Provided by Red Hat caching-nameserver package
//
// ISC BIND named zone configuration for zones recommended by
// RFC 1912 section 4.1 : localhost TLDs and address zones
// and http://www.ietf.org/internet-drafts/draft-ietf-dnsop-default-local-zones-02.txt
// (c)2007 R W Franks
//
// See /usr/share/doc/bind*/sample/ for example named configuration files.
//
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; };
};
--下面为增加的内容，jybd.net.forward为正向解析,jydba.net.reverse为反向解析
zone "jydba.net" IN {
type master;
file "jydba.net.forward";
allow-update { none; };
};
zone "130.138.10.in-addr.arpa" IN {
type master;
file "jydba.net.reverse";
allow-update { none; };
};
"/etc/named.rfc1912.zones" 54L, 1171C written
五.修改具体的zone配置文件
[root@jytest1 named]# cd /var/named
[root@jytest1 named]# cp named.localhost jydba.net.forward
[root@jytest1 named]# cp named.loopback jydba.net.reverse
[root@jytest1 named]# vi jydba.net.forward
$TTL 1D
@ IN SOA @ root.jydba.net. (
0 ; serial
1D ; refresh
1H ; retry
1W ; expire
3H ) ; minimum
NS @
A 10.138.130.171
AAAA ::1
jytest1 A 10.138.130.171
jytest2 A 10.138.130.172
jytest1-vip A 10.138.130.175
jytest2-vip A 10.138.130.176
jytest-scan A 10.138.130.177
jytest-scan A 10.138.130.178
jytest-scan A 10.138.130.179
[root@jytest1 named]# vi jydba.net.reverse
$TTL 1D
@ IN SOA @ root.jydba.net. (
0 ; serial
1D ; refresh
1H ; retry
1W ; expire
3H ) ; minimum
NS @
A 10.138.130.171
AAAA ::1
PTR localhost.
171 PTR jytest1
172 PTR jytest2
175 PTR jytest1-vip
176 PTR jytest2-vip
177 PTR jytest-scan
178 PTR jytest-scan
179 PTR jytest-scan
六.配置resolv.conf
[root@jytest1 named]# cat /etc/resolv.conf # Generated by NetworkManager search jydba.net # No nameservers found; try putting DNS servers into your # ifcfg files in /etc/sysconfig/network-scripts like so: # # DNS1=xxx.xxx.xxx.xxx # DNS2=xxx.xxx.xxx.xxx # DOMAIN=lab.foo.com bar.foo.com search jydba.net nameserver 10.138.130.171
七.测试
[root@jytest1 named]# dig -x 10.138.130.172 ; < <>> DiG 9.9.4-RedHat-9.9.4-18.el7 < <>> -x 10.138.130.172 ;; global options: +cmd ;; Got answer: ;; ->>HEADER< <- opcode: QUERY, status: REFUSED, id: 20870 ;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1 ;; WARNING: recursion requested but not available ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;172.130.138.10.in-addr.arpa. IN PTR ;; Query time: 6 msec ;; SERVER: 10.138.130.171#53(10.138.130.171) ;; WHEN: Fri Mar 17 19:15:47 CST 2017 ;; MSG SIZE rcvd: 56 [root@jytest1 named]# service named restart Redirecting to /bin/systemctl restart named.service [root@jytest1 named]# nslookup jytest1 Server: 10.138.130.171 Address: 10.138.130.171#53 ** server can't find jytest1: SERVFAIL
上面出现错误，server can't find jytest1: SERVFAIL，错误信息是因为之前创建文件时使用的是root用户，将这些创建的文件修改为named用户与组。
[root@jytest1 named]# ls -lrt total 32 -rw-r-----. 1 root named 152 Jun 21 2007 named.localhost -rw-r-----. 1 root named 168 Dec 15 2009 named.loopback -rw-r-----. 1 root named 152 Dec 15 2009 named.empty -rw-r-----. 1 root named 2076 Jan 28 2013 named.ca drwxrwx---. 2 root named 6 Mar 6 2015 dyndb-ldap drwxrwx---. 2 named named 6 Mar 6 2015 slaves drwxr-x---. 7 root named 56 Nov 5 11:03 chroot -rw-r----- 1 root named 728 Mar 17 18:45 named.jydba -rw-r--r-- 1 root root 829 Mar 17 18:45 jydba.zone drwxrwx---. 2 named named 22 Mar 17 18:45 data -rw-r----- 1 root root 503 Mar 17 19:13 jydba.net.forward -rw-r----- 1 root root 406 Mar 17 19:15 jydba.net.reverse drwxrwx---. 2 named named 58 Mar 17 19:16 dynamic [root@jytest1 named]# chown -R named:named jydba* [root@jytest1 named]# ls -lrt total 32 -rw-r-----. 1 root named 152 Jun 21 2007 named.localhost -rw-r-----. 1 root named 168 Dec 15 2009 named.loopback -rw-r-----. 1 root named 152 Dec 15 2009 named.empty -rw-r-----. 1 root named 2076 Jan 28 2013 named.ca drwxrwx---. 2 root named 6 Mar 6 2015 dyndb-ldap drwxrwx---. 2 named named 6 Mar 6 2015 slaves drwxr-x---. 7 root named 56 Nov 5 11:03 chroot -rw-r----- 1 root named 728 Mar 17 18:45 named.jydba -rw-r--r-- 1 named named 829 Mar 17 18:45 jydba.zone drwxrwx---. 2 named named 22 Mar 17 18:45 data -rw-r----- 1 named named 503 Mar 17 19:13 jydba.net.forward -rw-r----- 1 named named 406 Mar 17 19:15 jydba.net.reverse drwxrwx---. 2 named named 58 Mar 17 19:16 dynamic
[root@jytest1 named]# systemctl restart named.service [root@jytest1 named]# nslookup jytest1 Server: 10.138.130.171 Address: 10.138.130.171#53 Name: jytest1.jydba.net Address: 10.138.130.171 [root@jytest1 named]# nslookup jytest1.jydba.net Server: 10.138.130.171 Address: 10.138.130.171#53 Name: jytest1.jydba.net Address: 10.138.130.171 [root@jytest1 named]# nslookup jytest2-priv.jydba.net Server: 10.138.130.171 Address: 10.138.130.171#53 ** server can't find jytest2-priv.jydba.net: NXDOMAIN [root@jytest1 named]# nslookup jytest2-vip.jydba.net Server: 10.138.130.171 Address: 10.138.130.171#53 Name: jytest2-vip.jydba.net Address: 10.138.130.176 [root@jytest1 named]# nslookup jytest-scan.jydba.net Server: 10.138.130.171 Address: 10.138.130.171#53 Name: jytest-scan.jydba.net Address: 10.138.130.178 Name: jytest-scan.jydba.net Address: 10.138.130.179 Name: jytest-scan.jydba.net Address: 10.138.130.177 [root@jytest1 named]# nslookup 10.138.130.179 Server: 10.138.130.171 Address: 10.138.130.171#53 179.130.138.10.in-addr.arpa name = jytest-scan.130.138.10.in-addr.arpa.
通过测试可以看到DNS通过正向与反向解析都是正常的，说明配置成功。
注意:
对于Linux 使用NetworkManager来控制网络的操作系统，当主机重启之前/etc/resolv.conf文件可能会被重写。如果发生这种情况，需要对相应的网卡配置文件增加以下记录
对于Oracle Linux 6修改类似文件 /etc/sysconfig/network-scripts/ifcfg-eth0 (ifcfg-eth1 etc.)
对于Oracle Linux 7修改类似文/etc/sysconfig/network-scripts/ifcfg-ens160 (ifcfg-ens34 etc.)
DNS1=10.138.130.171
DOMAIN=jydba.net