Linux---管理网络

一、ip基础知识

1.ipv4

2进制32位-----10进制  

172.25.0.10/255.255.255.0

172.25.0.10：ip地址

255.255.255.0：子网掩码

子网掩码255位对应的ip位为网络位

子网掩码0对应的ip位为主机位

二、主机联网

主机有两块网卡：有线和无线；（有些没有无线可以买一个外置无线软盘）

注：如下操作都是root用户下的

route -n  查询网关

Kernel IP routing table

Destination     Gateway         Genmask         Flags Metric Ref   

0.0.0.0   (网关)  0.0.0.0         255.255.255.0          U

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右上角会出现无线表示

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选择网络：点击wi-fi按钮，turn o

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确认连上无线网，ping IP，如下连上网

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二、gateway 网关

1.路由器

主要功能是用来作nat的

dnat 目的地地址转换

snat 源地址转换  

2.网关

路由器上和自己处在同一个网段的那个ip  

3.设定网关

systemctl stop NetwrokManager

vim /etc/sysconfig/network   全局网关

GATEWAY=网关ip  

vim /etc/sysconfig/network-scripts/ifcfg-网卡配置文件  网卡接口网关

GATEWAY=网关ip

systemctl restart netwrok

4.将真机编程路由器

（1）开启火墙

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（2）设置火墙在开机时启动

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（3）ifconfig网卡

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可知网卡接口ip----br0:172.25.254.63;  wlp3so:192.168.43.253

5.将真机伪装成路由器

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伪装完成后，一定要reload

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6.虚拟机通过路由成功上网

（1）添加网络

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添加的网络，网关与真机ip一致

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关闭全局网络

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测试网络是连通的

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以上操作只能用地址访问

设定dns

vim /etc/resolv.conf

nameserver dns服务器ip

要想通过网络名称访问服务器，需 真机和虚拟机同时打开 vim /etc/resolv.conf

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此时能就能访问服务器了

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三、dsn

1.dns

dns是一台服务器

这太服务器提供了回答客户主机名和ip对应关系的功能

2.设定dns

vim /etc/resolv.conf

nameserver dns服务器ip

vim /etc/sysconfig/network-scripts/ifcfg-网卡配置文件

DNS1=dns服务器ip  

3.本地解析文件

vim /etc/hosts

ip 主机名称

4.本地解析文件和dns读取的优先级调整

/etc/nsswitch.conf

 38 hosts:     db files nisplus nis dns

 39 hosts:      files dns files代表本地解析文件，dns代表dns服务器，那个在前面那个优先  

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以上优先级不同，访问服务器速度不同

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四、配置ip

<<图形化>>

1.图形界面

nm-connection-editor

2.文本化图形

nmtui  

<<命令>>

ifconfig 网卡 ip netmask  临时设定

<<文件>>  

static|none ##静态网络

vim /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE=eth0  ##设备

BOOTPROTO=static|none  ##设备工作方式

ONBOOT=yes  ##开启网络服务激活设备

NAME=eth0  ##网络接口名称

IPADDR=172.25.0.100   ##IP

NETMASK=255.255.255.0 | PREFIX=24 ##子网掩码

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dhcp ##动态获取

vim /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE=eth0 ##接口使用设备

BOOTPROTO=dhcp ##网卡工作模式

ONBOOT=yes ##网络服务开启时自动激活

NAME=eth0 ##网络接口名称

：wq

systemctl restart networ

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nmcli connection add type ethernet con-name nameifname eth0 autoconnect yes  添加dhcp网络

nmcli connection add type ethernet con-name name ifname eth0 ip4 ip/24  添加静态网络

nmcli connection delete name  删除name链接

nmcli connection show   显示所有网络链接

nmcli connection down name  关闭指定链接

nmcli connection up name 开启指定链接

nmcli connection modify "name" ipv4.addresses newip/24  改变name的ip

nmcli connection modify "name" ipv4.method <auto|manual>  改变name的工作方式为动态或者静态

nmcli device connect eth0  开启设备

nmcli device disconnect eth0  关闭设备

nmcli device show   显示设备信息

nmcli device status  显示设备状态

nmcli connection add type ethernet con-name nameifname eth0 autoconnect yes  添加dhcp网络

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nmcli connection delete didi 删除didi

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nmcli connection show 显示所有网络

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nmcli connection add type ethernet con-name name ifname eth0 ip4 ip/24  添加静态网络

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nmcli connection modify "didi" ipv4.addresses newip/24  改变didi的ip

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nmcli connnection modiy "didi" ipv4.method auto 改变didi的工作状态为动态

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nmcli connnection modiy "didi" ipv4.method manual 改变didi的工作状态为静态

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nmcli device connect eth0 开启设备

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nmcli device disconnect eth0 关闭设备

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nmcli device show 显示设备信息

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nmcli device status 显示设备状态

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原文：http://13363488.blog.51cto.com/13353488/1974013