Linux网络配置

目录

查看网络接口信息

ifconfig：查看所有网络接口信息

​编辑

临时配置网址

网络接口配置文件：

ip：查看设备ip地址

hostname 修改主机名

ethtool 显示网卡的详细信息

route 查看路由表

netstat 查看网络连接情况

ss（socket statistics）内核搜索

ping 测试网络连接性

traceroute 路由追踪

nslookup 域名解析

---

查看网络接口信息

ifconfig：查看所有网络接口信息

语法：

ifconfig [网络接口名称]：查看网络接口信息

通常查看ens33接口

[ens33]：

• en：Ether Net，表示网卡类型为以太网

• s：表示热插拔卡槽上的设备（hot-plug Slot）

• 33：表示插槽编号

centos6的默认网卡是eth0（eth0是自定义名称）

centos7的默认网卡是ens33（ens33代表以太网第33号接口）

<span style="background-color:#dadada"><span style="color:#1f0909"> [root@localhost ~]<span style="color:#aa5500">#ifconfig ens33</span>
 ens33<span style="color:#0000ff">:flags</span><span style="color:#981a1a">=</span><span style="color:#116644">4163</span><up,BROADCAST,RUNNING,MULTICAST> mut <span style="color:#116644">1500</span>
        <span style="color:#aa5500">#    接口已启用，支持广播，正在运行，支持组播    最大传输单元1500字节  </span>
        inet <span style="color:#116644">192</span>.168.190.129  netmask <span style="color:#116644">255</span>.255.255.0  broadcast <span style="color:#116644">192</span>.168.190.255  
        <span style="color:#aa5500">#    ip地址                    子网掩码                  广播地址</span>
        inet6 fe80::6e7:f7a9:1cd6:166e  prefixlen <span style="color:#116644">64</span>  scopeid 0x2<link>
        <span style="color:#aa5500">#     IPV6地址                   子网长度       作用域，link：仅该接口有效</span>
        ether <span style="color:#116644">00</span>:0c:29:38:ef:61  txqueuelen <span style="color:#116644">1000</span>  (Ethernet)
        <span style="color:#aa5500">#     mac地址             传输队列长度        接口类型：以太网</span>
        RX packets <span style="color:#116644">2943</span>  bytes <span style="color:#116644">234118</span> (228.6 KiB)
        <span style="color:#aa5500">#接收 报文个数     字节数总和</span>
        RX errors <span style="color:#116644">0</span>  dropped <span style="color:#116644">0</span>  overruns <span style="color:#116644">0</span>  frame <span style="color:#116644">0</span>
        <span style="color:#aa5500">#接收 错误    丢弃        溢出         冲突帧数</span>
        TX packets <span style="color:#116644">1133</span>  bytes <span style="color:#116644">135986</span> (132.7 KiB)
        <span style="color:#aa5500">#发送 报文个数     字节数总和 </span>
        TX errors <span style="color:#116644">0</span>  dropped <span style="color:#116644">0</span> overruns <span style="color:#116644">0</span>  carrier <span style="color:#116644">0</span>  collisions
        <span style="color:#aa5500">#发送 错误    丢弃       溢出         载荷数      冲突</span></span></span>

临时配置网址

• ifconfig 网卡名 ip地址及端口号：临时设置IP地址

<span style="background-color:#dadada"><span style="color:#1f0909"> [root@localhost ~]<span style="color:#aa5500">#ifconfig ens33 192.168.190.66/24</span>
 [root@localhost ~]<span style="color:#aa5500">#ifconfig ens33</span>
 ens33<span style="color:#0000ff">:flags</span><span style="color:#981a1a">=</span><span style="color:#116644">4163</span><up,BROADCAST,RUNNING,MULTICAST> mut <span style="color:#116644">1500</span>
       inet <span style="color:#116644">192</span>.168.190.66  netmask <span style="color:#116644">255</span>.255.255.0  broadcast <span style="color:#116644">192</span>.168.190.255 
       <span style="color:#aa5500">#IP地址修改为192.168.190.66</span>
       <span style="color:#aa5500">#临时修改，重启后失效</span></span></span>

• ifconfig  网卡名：数字 ip地址/子网掩码：设置虚拟网卡，临时测试使用

• ifconfig 网卡名 down：关闭网卡（等同于ifdown ens33）

• ifconfig  -a：查看所有网卡

• ifconfig  -s：查看网络通讯情况

网络接口配置文件：

• /etc/sysconfig/network-scripts/目录下

<span style="background-color:#dadada"><span style="color:#1f0909"> ifcfg-ens33
 <span style="color:#aa5500">#第一块网卡配置文件</span>
 ​
 [root@localhost ~]<span style="color:#aa5500">#vim /etc/sysconfig/neywork-scripts/ifcfg-ens33</span>
 <span style="color:#0000ff">DEVICE</span><span style="color:#981a1a">=</span>ens33
 <span style="color:#0000ff">BOOTPROTO</span><span style="color:#981a1a">=</span>static
 <span style="color:#0000ff">ONBOOT</span><span style="color:#981a1a">=</span><span style="color:#3300aa">yes</span>
 <span style="color:#0000ff">IPADDR</span><span style="color:#981a1a">=</span><span style="color:#116644">192</span>.168.190.2
 <span style="color:#0000ff">NETMASK</span><span style="color:#981a1a">=</span><span style="color:#116644">255</span>.255.255.0
 <span style="color:#0000ff">GATEWAY</span><span style="color:#981a1a">=</span><span style="color:#116644">192</span>.168.190.129
 <span style="color:#0000ff">DNS1</span><span style="color:#981a1a">=</span><span style="color:#116644">192</span>.168.180.10
 <span style="color:#0000ff">DNS2</span><span style="color:#981a1a">=</span><span style="color:#116644">192</span>.168.170.20
 ​
 [root@localhost ~]<span style="color:#aa5500">#systemctl restart network</span>
 <span style="color:#aa5500">#重启网络服务</span></span></span>

ip：查看设备ip地址

常用命令：ip a

临时修改网卡名称：

<span style="background-color:#dadada"><span style="color:#1f0909"> ip link <span style="color:#770088">set</span> ens33 down
 <span style="color:#aa5500">#首先将原网卡ens33关掉</span>
 ip link <span style="color:#770088">set</span> ens33 name net1
 <span style="color:#aa5500">#修改网卡的名称为net1</span>
 ip link <span style="color:#770088">set</span> net1 up
 <span style="color:#aa5500">#最后重新启动网卡</span></span></span>

永久修改网卡名称：

<span style="background-color:#dadada"><span style="color:#1f0909"> [root@test1 ~]<span style="color:#aa5500">#vim /etc/default/grub</span>
 <span style="color:#0000ff">GRUB_TIMEOUT</span><span style="color:#981a1a">=</span><span style="color:#116644">5</span>
 <span style="color:#0000ff">GRUB_DISTRIBUTOR</span><span style="color:#981a1a">=</span><span style="color:#aa1111">"</span><span style="color:#009900">$(sed 's,release .*</span><span style="color:#0000ff">$,</span><span style="color:#009900">,g' /etc/system-release)</span><span style="color:#aa1111">"</span>
 <span style="color:#0000ff">GRUB_DEFAULT</span><span style="color:#981a1a">=</span>saved
 <span style="color:#0000ff">GRUB_DISABLE_SUBUMENU</span><span style="color:#981a1a">=</span><span style="color:#221199">true</span>
 <span style="color:#0000ff">GRUB_TERMIANL_OUTPUT</span><span style="color:#981a1a">=</span><span style="color:#aa1111">"console"</span>
 <span style="color:#0000ff">GRUB_CMDLINE_LINUX</span><span style="color:#981a1a">=</span><span style="color:#aa1111">"crashkernel=auto rd.lvm.lv=centos/swap rhgb quit net.ifnames=0"</span>
 <span style="color:#aa5500">#在上方行加入 net.ifnames=0</span>
 <span style="color:#0000ff">GRUB_DISABLE_RECOVERY</span><span style="color:#981a1a">=</span><span style="color:#aa1111">"true"</span>
 ​
 [root@localhost ~]<span style="color:#aa5500">#grub2-mkconfig -o /boot/grub2/grub.cfg</span>
 <span style="color:#aa5500">#统一网卡名称</span>
 ​
 [root@localhost ~]<span style="color:#aa5500">#reboot</span>
 [root@localhost ~]<span style="color:#aa5500">#ifconfig</span>
 [root@localhost ~]<span style="color:#aa5500">#cd /etc/sysconfig/network-scripts/</span>
 [root@localhost ~]<span style="color:#aa5500">#ls</span>
 [root@localhost ~]<span style="color:#aa5500">#vim /ifcfg-ens33</span>
 <span style="color:#116644">1</span> <span style="color:#0000ff">TPE</span><span style="color:#981a1a">=</span>Ethernet
   <span style="color:#116644">2</span> <span style="color:#0000ff">PROXY_METHOD</span><span style="color:#981a1a">=</span>none
   <span style="color:#116644">3</span> <span style="color:#0000ff">BROWSER_ONLY</span><span style="color:#981a1a">=</span>no
   <span style="color:#116644">4</span> <span style="color:#0000ff">BOOTPROTO</span><span style="color:#981a1a">=</span>dhcp
   <span style="color:#116644">5</span> <span style="color:#0000ff">DEFROUTE</span><span style="color:#981a1a">=</span><span style="color:#3300aa">yes</span>
   <span style="color:#116644">6</span> <span style="color:#0000ff">IPV4_FAILURE_FATAL</span><span style="color:#981a1a">=</span>no
   <span style="color:#116644">7</span> <span style="color:#0000ff">IPV6INIT</span><span style="color:#981a1a">=</span><span style="color:#3300aa">yes</span>
   <span style="color:#116644">8</span> <span style="color:#0000ff">IPV6_AUTOCONF</span><span style="color:#981a1a">=</span><span style="color:#3300aa">yes</span>
   <span style="color:#116644">9</span> <span style="color:#0000ff">IPV6_DEFROUTE</span><span style="color:#981a1a">=</span><span style="color:#3300aa">yes</span>
  <span style="color:#116644">10</span> <span style="color:#0000ff">IPV6_FAILURE_FATAL</span><span style="color:#981a1a">=</span>no
  <span style="color:#116644">11</span> <span style="color:#0000ff">IPV6_ADDR_GEN_MODE</span><span style="color:#981a1a">=</span>stable-privacy
  <span style="color:#116644">12</span> <span style="color:#0000ff">NAME</span><span style="color:#981a1a">=</span>ens33
  <span style="color:#aa5500">#删除name行,或改为net1</span>
  <span style="color:#116644">13</span> <span style="color:#0000ff">UUID</span><span style="color:#981a1a">=</span>f432e08c-147d-41de-8c75-17d26b7737ad
  <span style="color:#116644">14</span> <span style="color:#0000ff">DEVICE</span><span style="color:#981a1a">=</span>net1
  <span style="color:#aa5500">#将device改为net1</span>
  <span style="color:#116644">15</span> <span style="color:#0000ff">ONBOOT</span><span style="color:#981a1a">=</span>no
 ​
 [root@localhost ~]<span style="color:#aa5500">#systemctl restart network</span>
 [root@localhost ~]<span style="color:#aa5500">#ifconfig</span></span></span>

hostname 修改主机名

临时修改主机名：

<span style="background-color:#dadada"><span style="color:#1f0909"> [root@localhost ~]<span style="color:#aa5500">#hostname wang</span>
 [root@wang ~]<span style="color:#aa5500">#</span>
 <span style="color:#aa5500">#临时修改，重启后还原</span>
 [root@wang ~]<span style="color:#aa5500">#reboot</span>
 [root@localhost ~]<span style="color:#aa5500">#</span></span></span>

永久修改主机名：

<span style="background-color:#dadada"><span style="color:#1f0909"> CentOS <span style="color:#116644">7</span>
 方法一：
 [root@localhost ~]<span style="color:#aa5500">#hostnamectl set-hostname wang</span>
 <span style="color:#aa5500">#重启后生效</span>
 [root@localhost ~]<span style="color:#aa5500">#reboot</span>
 [root@wang ~]<span style="color:#aa5500">#</span>
 方法二：
 [root@localhost ~]<span style="color:#aa5500">#vim /etc/hostname</span>
 wang
 <span style="color:#aa5500">#将原来的名称localhost改为wang</span>
 <span style="color:#aa5500">#只对第一行的名称生效，下面写其他内容无效</span>
 ​
 [root@localhost ~]<span style="color:#aa5500">#reboot</span>
 [root@wang ~]<span style="color:#aa5500">#</span>
 ​
 ​
 CentOS <span style="color:#116644">6</span>
 [root@localhost ~]<span style="color:#aa5500">#vim /etc/sysconfig/network</span>
 <span style="color:#0000ff">NETWORKING</span><span style="color:#981a1a">=</span><span style="color:#3300aa">yes</span>
 <span style="color:#0000ff">HOSTNAME</span><span style="color:#981a1a">=</span>localhost.localdomain
 <span style="color:#aa5500">#将原来的hostname修改</span>
 <span style="color:#aa5500">#保存并重启</span>
 ​</span></span>

ethtool 显示网卡的详细信息

• ethtool -i ens33：查看网卡详细信息

• ethtool -p ens33：让ens33网卡端口快速闪烁

route 查看路由表

• route -n：查看默认路由条目

• 添加路由：route add -net IP地址/子网掩码 gw 下一跳地址

<span style="background-color:#dadada"><span style="color:#1f0909"> [root@localhost ~]<span style="color:#aa5500">#route add -net 192.168.100.0/24 gw 192.168.190.129</span>
 <span style="color:#aa5500">#                                 添加的网段及子网掩码   连接的下一跳地址</span>
 [root@localhost ~]<span style="color:#aa5500">#route -n</span>
 Kernel IP routing table
 Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
 <span style="color:#116644">0</span>.0.0.0         <span style="color:#116644">192</span>.168.190.2   <span style="color:#116644">0</span>.0.0.0         UG    <span style="color:#116644">100</span>    <span style="color:#116644">0</span>        <span style="color:#116644">0</span> ens33
 <span style="color:#116644">192</span>.168.100.0   <span style="color:#116644">192</span>.168.190.129 <span style="color:#116644">255</span>.255.255.0   UG    <span style="color:#116644">0</span>      <span style="color:#116644">0</span>        <span style="color:#116644">0</span> ens33
 <span style="color:#116644">192</span>.168.122.0   <span style="color:#116644">0</span>.0.0.0         <span style="color:#116644">255</span>.255.255.0   U     <span style="color:#116644">0</span>      <span style="color:#116644">0</span>        <span style="color:#116644">0</span> virbr0
 <span style="color:#116644">192</span>.168.190.0   <span style="color:#116644">0</span>.0.0.0         <span style="color:#116644">255</span>.255.255.0   U     <span style="color:#116644">100</span>    <span style="color:#116644">0</span>        <span style="color:#116644">0</span> ens33
 <span style="color:#aa5500">#可以看到添加了一个新的网段192.168.100.0</span></span></span>

• 删除路由：route del -net 网段/子网掩码

<span style="background-color:#dadada"><span style="color:#1f0909"> [root@localhost ~]<span style="color:#aa5500">#route del -net 192.168.100.0/24</span>
 <span style="color:#aa5500">#                                 要删除的网段及子网掩码</span>
 [root@localhost ~]<span style="color:#aa5500">#route -n</span>
 Kernel IP routing table
 Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
 <span style="color:#116644">0</span>.0.0.0         <span style="color:#116644">192</span>.168.190.2   <span style="color:#116644">0</span>.0.0.0         UG    <span style="color:#116644">100</span>    <span style="color:#116644">0</span>        <span style="color:#116644">0</span> ens33
 <span style="color:#116644">192</span>.168.122.0   <span style="color:#116644">0</span>.0.0.0         <span style="color:#116644">255</span>.255.255.0   U     <span style="color:#116644">0</span>      <span style="color:#116644">0</span>        <span style="color:#116644">0</span> virbr0
 <span style="color:#116644">192</span>.168.190.0   <span style="color:#116644">0</span>.0.0.0         <span style="color:#116644">255</span>.255.255.0   U     <span style="color:#116644">100</span>    <span style="color:#116644">0</span>        <span style="color:#116644">0</span> ens33
 <span style="color:#aa5500">#此时网段192.168.100.0已删除</span></span></span>

• 删除默认路由：

<span style="background-color:#dadada"><span style="color:#1f0909"> [root@localhost ~]<span style="color:#aa5500">#route del default</span></span></span>

• 重新添加路由：

<span style="background-color:#dadada"><span style="color:#1f0909"> [root@localhost ~]<span style="color:#aa5500">#route add default gw 192.168.190.129</span></span></span>

内核调优：开启路由转发

• Linux系统本身是没有转发功能的，只有路由发送数据

<span style="background-color:#dadada"><span style="color:#1f0909"> [root@localhost network-scripts]<span style="color:#aa5500">#tcpdump -i ens33 -nn icmp</span>
 ​
 临时打开：
 [root@localhost network-scripts]<span style="color:#aa5500">#echo 1 > /proc/sys/net/ipv4/ip_sforward</span>
 或
 [root@localhost network-scripts]<span style="color:#aa5500">#sysctl -w net.ipv4.ip_forward=1</span>
 ​
 永久打开：
 [root@localhost ~]<span style="color:#aa5500">#vim /etc/sysctl.conf</span>
 net.ipv4.ip_forward <span style="color:#981a1a">=</span> <span style="color:#116644">1</span>
 <span style="color:#aa5500">#将配置写入文件</span>
  
 [root@localhost ~]<span style="color:#aa5500">#sysctl -p</span>
 <span style="color:#aa5500">#读取修改后的配置</span></span></span>

netstat 查看网络连接情况

功能与ss相似

语法：

netstat [选项] 

[选项]：

• -a：显示主机中所有活动的网络连接信息（包括监听、非监听状态的服务端口）

• -n：以数字的形式显示相关的主机地址、端口等信息

• -r：显示路由表信息

• -l：显示处于监听（Listening）状态的网络连接及端口信息

• -t：查看 TCP（Transmission Control Protocol，传输控制协议）相关的信息

• -u：显示 UDP（User Datagram Protocol，用户数据报协议）协议相关的信息

• -p：显示与网络连接相关联的进程号、进程名称信息（该选项需要 root 权限）

<span style="background-color:#dadada"><span style="color:#1f0909"> [root@test ~]<span style="color:#aa5500">#systemctl start httpd</span>
 [root@test ~]<span style="color:#aa5500">#netstat -ntap |grep 80</span>
 tcp        <span style="color:#116644">0</span>      <span style="color:#116644">0</span> <span style="color:#116644">0</span>.0.0.0:22              <span style="color:#116644">0</span>.0.0.0:*               LISTEN      <span style="color:#116644">6809</span>/sshd           
 tcp        <span style="color:#116644">0</span>      <span style="color:#116644">0</span> <span style="color:#116644">192</span>.168.190.130:42016   <span style="color:#116644">60</span>.191.80.11:80         TIME_WAIT   <span style="color:#0000cc">-</span>                   
 tcp        <span style="color:#116644">0</span>      <span style="color:#116644">0</span> <span style="color:#116644">192</span>.168.190.130:42004   <span style="color:#116644">60</span>.191.80.11:80         TIME_WAIT   <span style="color:#0000cc">-</span>                   
 tcp        <span style="color:#116644">0</span>      <span style="color:#116644">0</span> <span style="color:#116644">192</span>.168.190.130:42020   <span style="color:#116644">60</span>.191.80.11:80         TIME_WAIT   <span style="color:#0000cc">-</span>                   
 tcp        <span style="color:#116644">0</span>      <span style="color:#116644">0</span> <span style="color:#116644">192</span>.168.190.130:51610   <span style="color:#116644">202</span>.141.160.110:80      TIME_WAIT   <span style="color:#0000cc">-</span>                   
 tcp6       <span style="color:#116644">0</span>      <span style="color:#116644">0</span> :::80                   :::*                    LISTEN      <span style="color:#116644">15617</span>/httpd         
 tcp6       <span style="color:#116644">0</span>      <span style="color:#116644">0</span> :::22                   :::*                    LISTEN      <span style="color:#116644">6809</span>/sshd 
 [root@test ~]<span style="color:#aa5500">#netstat -ntap |grep ":22"</span>
 tcp        <span style="color:#116644">0</span>      <span style="color:#116644">0</span> <span style="color:#116644">0</span>.0.0.0:22              <span style="color:#116644">0</span>.0.0.0:*               LISTEN      <span style="color:#116644">6809</span>/sshd           
 tcp        <span style="color:#116644">0</span>     <span style="color:#116644">36</span> <span style="color:#116644">192</span>.168.190.130:22      <span style="color:#116644">192</span>.168.190.1:10422     ESTABLISHED <span style="color:#116644">12298</span>/sshd: root@pt 
 tcp6       <span style="color:#116644">0</span>      <span style="color:#116644">0</span> :::22                   :::*                    LISTEN      <span style="color:#116644">6809</span>/sshd     
 ​</span></span>

ss（socket statistics）内核搜索

• 查看网络连接状况，但主要用于获取socket（内核态）统计信息，比用户态更加直接

• 能够显示更多更详细的有关TCP和连接状态的信息，比netstat更加快速、高效

• 利用TCP协议栈中的tcp_diag，他是一个用于分析统计的模块，可以获得内核中的第一手信息

语法：

ss [选项]

[选项]：

• -t：tcp协议相关，只显示tcp协议

• -u：udp协议相关，只显示udp协议

• -w：裸套接字相关

• -x：unix sock相关

• -l：listen状态的连接

• -a：所有

• -n：数字格式

• -p：相关的程序及PID

• -e：扩展的信息

• -m：内存用量

• -o：计时器信息

• -r：--resolve 把 IP 解释为域名，把端口号解释为协议名称。 dns 服务

可以与time命令比较：time ss -atn

常用命令：

• ss -natp

• ss -naup

ping 测试网络连接性

常用命令：

• ping -c：发送多少个包

• ping -w：表示等待10秒

traceroute 路由追踪

• traceroute IP地址

nslookup 域名解析

• nslookup 域名

• dig：显示更多详细信息

CDN：缓存服务器，内容分发网络（静态资源)

DNS：

<span style="background-color:#dadada"><span style="color:#1f0909"> 配置文件：
 /etc/resolv.conf
 ​
 [root@localhost ~]<span style="color:#aa5500">#vim /etc/resolv.conf</span>
 search localdomain
 nameserver <span style="color:#116644">202</span>.106.0.20
 nameserver <span style="color:#116644">202</span>.106.148.1
 <span style="color:#aa5500">#CentOS 7需要再NetworkManager.conf文件main段内设置dns=none,并重启NetworkManager服务，或者使用CentOS 7新添加nmcil命令进行设置</span>
 ​</span></span>

补充：nslookup、dns、cdn等都与电商平台有关

重要文件路径：（服务器开启时优先检索以下文件）

• /etc/hostname：主机名与IP地址的映射记录

• /etc/hosts：域名解析文件，优先级最高

• /etc/resolv.conf：域名解析服务器地址

本章重要命令：

• route -n：查看网关

• ifconfig：查看IP地址

• nslookup：解析域名（Linux和Windows通用命令）

修改网卡配置

DEVICE=

BOOTPROTO=

ONBOOT=

IPADDR=

NETMAK(PREFIX)=

GATEWAY=

DNS1=

DNS2=