Linux下的網絡管理-DNS

一.DNS

dns: 負責作域名轉換成ip這個工作的主機叫做dns服務器（地址解析）
1.DNS指向性文件

vim /etc/resolv.conf ##dns服務器指向文件臨時
nameserver 114.114.114.114 ##114.114.114.114 爲電信dns服務器

當我們去訪問ping www.baidu.com ，去詢問指向性文件 /etc/resolv.conf 裏的114.114.114.114 www.baidu.com對應的ip是多少
www.baidu.com = 39.156.66.18
2.本地解析

vim /etc/hosts ##叫做本地解析文件
39.156.66.18 www.baidu.com

3.DNS永久設定

vim /etc/sysconfig/network-scripts/ifcfg-ens160 ##dns的永久設定
DNS1=114.114.114.114

注意：設置完成後重啓網絡服務

DNS實驗

1.設定主機ip和windows在一個網段

2.設定主機網關和windows相同

[root@rhel7 ~]# vim /etc/sysconfig/network-scripts/ifcfg-ens33
DEVICE=ens33
ONBOOT=yes
BOOTPROTO=none
IPADDR=192.168.1.10
NETMASK=255.255.255.0
GATEWAY=192.168.1.1

3.在windows中ping www.baidu.com 查看百度ip

4.在linux中可以ping通百度ip

[root@rhel7 ~]# ping 61.135.169.125
PING 61.135.169.125 (61.135.169.125) 56(84) bytes of data.
64 bytes from 61.135.169.125: icmp_seq=1 ttl=55 time=76.0 ms
64 bytes from 61.135.169.125: icmp_seq=2 ttl=55 time=16.0 ms

5.在linux中ping www.baidu.com 不可以

[root@rhel7 network-scripts]# ping www.baidu.com
ping: www.baidu.com: Name or service not known

6.編寫本地解析文件/etc/hosts
61.135.169.125 www.baidu.com
ping www.baidu.com 可以

[root@rhel7 network-scripts]# ping www.baidu.com
PING www.baidu.com (61.135.169.121) 56(84) bytes of data.
64 bytes from www.baidu.com (61.135.169.121): icmp_seq=1 ttl=55 time=16.1 ms
64 bytes from www.baidu.com (61.135.169.121): icmp_seq=2 ttl=55 time=17.9 ms

ping www.qq.com 不可以

[root@rhel7 network-scripts]# ping www.qq.com
ping: www.qq.com: Name or service not known

7.指向性文件/etc/resolv.conf
nameserver 114.114.114.114
ping www.qq.com 可以

[root@rhel7 network-scripts]# ping www.qq.com
PING public-v6.sparta.mig.tencent-cloud.net (220.194.111.148) 56(84) bytes of data.
64 bytes from dns148.online.tj.cn (220.194.111.148): icmp_seq=1 ttl=55 time=23.8 ms
64 bytes from dns148.online.tj.cn (220.194.111.148): icmp_seq=2 ttl=55 time=21.1 ms