CentOS8配置本地DNS

为了完成VCSA的完整安装。需要在本地配置一台RedHat8的vm来作为本地的DNS

1.安装DNS服务

查询bind

[root@vm2 ~]# yum info bind

安装bind

[root@vm2 ~]# yum -y install bind
[root@vm2 ~]# rpm -ql bind

 查看13个根域服务器文件：

[root@vm2 ~]# cat /var/named/named.ca

 开启DNS服务,并添加防火墙端口：

[root@vm2 ~]# systemctl start named
[root@vm2 ~]# systemctl enable named
Created symlink /etc/systemd/system/multi-user.target.wants/named.service → /usr/lib/systemd/system/named.service.
[root@vm2 ~]# firewall-cmd --permanent --add-service=dns
success
[root@vm2 ~]# firewall-cmd --permanent --add-port=53/tcp
success
[root@vm2 ~]# firewall-cmd --permanent --add-port=53/udp
success

[root@vm2 ~]# firewall-cmd --reload
success
[root@vm2 ~]# ss -untl

查看修改网卡信息：

[root@vm2 ~]# vim /etc/sysconfig/network-scripts/ifcfg-ens192

PEERDNS= "no"

 电脑重启后 /etc/resolv.conf 的namespace不会恢复至系统默认

[root@vm2 ~]# systemctl restart network-online.target

编辑DNS配置文件/etc/named.conf文件：

[root@vm2 etc]# cp -p /etc/named.conf{,.back}

[root@vm2 etc]# ll |grep named.conf
-rw-r-----.  1 root named     1705 Feb 18  2021 named.conf
-rw-r-----.  1 root named     1705 Feb 18  2021 named.conf.back

[root@vm2 etc]# vim named.conf

[root@vm2 etc]# cat 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 { 127.0.0.1; };
    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";
    secroots-file    "/var/named/data/named.secroots";
    recursing-file    "/var/named/data/named.recursing";
    allow-query     { localhost; };

    /* 
     - 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;

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

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

    /* https://fedoraproject.org/wiki/Changes/CryptoPolicy */
    include "/etc/crypto-policies/back-ends/bind.config";
};

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

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

zone "example.com" IN {
        type master;
        file "example.com.zone";
};

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

[root@vm2 etc]# systemctl reload named
[root@vm2 etc]# ss -ntul

[root@vm2 etc]# cat /etc/resolv.conf
# Generated by NetworkManager
search example.com