User & Group Management

Switch User

Switch current user to root:

[user@localhost /]# su root

User Operations

Create user user01 and set password:

[root@localhost /]# useradd user01
[root@localhost /]# passwd user01

Create user user02 with shell /bin/sh and home directory /etc/user02:

[root@localhost /]# useradd -s /bin/sh -d /etc/user02 -m user02

Delete user user01:

[root@localhost /]# userdel -r user01

Change user inf login shell to /bin/inf, home to /home/inf, group to developer:

[root@localhost /]# usermod -s /bin/inf -d /home/inf -g developer inf

Group Operations

Create group01:

[root@localhost /]# groupadd group01

Create group01 with GID 101:

[root@localhost /]# groupadd -g 101 group01

Delete group01:

[root@localhost /]# groupdel group01

Add user user01 to group01:

[root@localhost /]# usermod -g group01 user01

Configure Local NIC

Disable SELinux:

[root@localhost /]# setenforce 0

Stop firewalld.service:

[root@localhost /]# systemctl stop firewalld.service

Edit network config:

[root@localhost /]# vi /etc/sysconfig/network-scripts/ifcfg-enol16777736

HWADDR=00:0C:29:5F:F4:0C
TYPE=Ethernet
BOOTPROTO=static
DEFROUTE=yes
PEERDNS=yes
PEERROUTES=yes
NAME=eno16777736
UUID=003511d8-aaf9-4c76-8c19-aadc1a84a504
ONBOOT=yes
IPADDR=192.168.8.1
NETMASK=255.255.255.0
DNS1=192.168.8.1

Restart network service:

[root@localhost /]# systemctl restart network

Mount Image & Install DNS Service

Create /mnt/cdrom and mount /dev/cdrom:

[root@localhost /]# mkdir /mnt/cdrom
[root@localhost /]# mount /dev/cdrom /mnt/cdrom
mount: /dev/sr0 is write-protected, mounting read-only

Enter /etc/yum.repos.d/ and delete all files:

[root@localhost /]# cd /etc/yum.repos.d/
[root@localhost yum.repos.d]# rm -rf *

Configure yum repo:

[root@localhost yum.repos.d]# vi a.repo

[a]
name=a
baseurl=file:///mnt/cdrom
enable=1
gpgcheck=0

Install bind (DNS service):

[root@localhost yum.repos.d]# yum install -y bind*

DNS Service Configuration

Main Configuration

Edit main config, delete lines 45 & 10, change lines 14-15 to no:

[root@localhost yum.repos.d]# vi /etc/named.conf

options {
         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";

         recursion yes;

         dnssec-enable no;
         dnssec-validation no;
         dnssec-lookaside auto;
};

Zone Configuration

Add zones at end of file:

[root@localhost yum.repos.d]# vi /etc/named.rfc1912.zones

zone "baidu.com" IN {
    type master;
    file "a";
    allow-update { none; };
};
zone "qq.cn" IN {
    type master;
    file "a1";
    allow-update { none; };
};
zone "8.168.192.in-addr.arpa" IN {
    type master;
    file "fx";
    allow-update { none; };
};
zone "58.168.192.in-addr.arpa" IN {
    type master;
    file "fx1";
    allow-update { none; };
};

Enter /var/named/, copy default files:

[root@localhost yum.repos.d]# cd /var/named/
[root@localhost named]# cp -p named.localhost a
[root@localhost named]# cp -p named.localhost a1
[root@localhost named]# cp -p named.loopback fx
[root@localhost named]# cp -p named.loopback fx1

Forward Zone Files

Edit a:

[root@localhost named]# vi a

$TTL 1D
@    IN SOA    www.baidu.com. rname.invalid. (
                    0   ; serial
                    1D  ; refresh
                    1H  ; retry
                    1W  ; expire
                    3H )  ; minimum
    IN  NS    www
www   IN  A    192.168.8.1
txt   IN  A    192.168.58.1

Edit a1:

[root@localhost named]# vi a1

$TTL 1D
@    IN SOA    dns.qq.cn. rname.invalid. (
                    0   ; serial
                    1D  ; refresh
                    1H  ; retry
                    1W  ; expire
                    3H )  ; minimum
    IN  NS    dns
dns   IN  A    192.168.8.2
web   IN  A    192.168.58.2

Reverse Zone Files

Edit fx:

$TTL 1D
@    IN SOA    www.baidu.com. rname.invalid. (
                    0   ; serial
                    1D  ; refresh
                    1H  ; retry
                    1W  ; expire
                    3H )  ; minimum
    IN  NS    www.baidu.com.
1    IN  PTR   www.baidu.com.
2    IN  PTR   dns.qq.cn.

Edit fx1:

$TTL 1D
@    IN SOA    txt.baidu.com. rname.invalid. (
                    0   ; serial
                    1D  ; refresh
                    1H  ; retry
                    1W  ; expire
                    3H )  ; minimum
    IN  NS    txt.baidu.com.
1    IN  PTR   txt.baidu.com.
2    IN  PTR   web.qq.cn.

Restart DNS and test:

[root@localhost named]# systemctl restart named
[root@localhost named]# nslookup
> www.baidu.com
Server:        192.168.8.1
Address:    192.168.8.1#53

Name:       www.baidu.com
Address:   192.168.8.1

> 192.168.8.1
Server:        192.168.8.1
Address:    192.168.8.1#53

1.8.168.192.in-addr.arpa   name = www.baidu.com.

Finish