Linux Network Configuration Guide: Easily Set Up IPv4 and IPv6 Addresses

Linux Configuration of IPv4 or IPv6 Addresses

Configuration

Configuration Introduction

  • • View Network

    ifconfig

  • • Network Interface Introduction
    • • <span>eth0</span> : Local network interface (CentOS7 uses ens33)
    • • <span>lo</span> : Internal network interface, manages internal IP, which is the 127.0.0.1 address
    • • <span>virbr0</span> : Virtual network interface
  • • Configuration File <span>ifcfg-<interface></span>
    • • <span>ifcfg-eth0</span> : Configuration file for the interface <span>eth0</span> (both <span>ipv4</span> and <span>ipv6</span> are configured in this file)
    • • <span>ifcfg-lo</span> : Configuration file for the interface <span>lo</span> Tips: Configuration files are located in the directory <span>/etc/sysconfig/network-scripts/</span>;

Automatically Obtain Address

IPv4 is set to automatically obtain an address by default, no configuration is needed; the following is the configuration to enable automatic address acquisition for IPv6

  1. 1. Modify the <span>/etc/sysconfig/network</span> file 
    |     |     |
| --- | --- |
|     | # Enable network IPv4 |
|     | NETWORKING=yes |
|     |     |
|     | # Enable network IPv6, add if not present, some machines have it enabled by default |
|     | NETWORKING_IPV6=yes |
|     |     |
|     | # Hostname, takes effect after restart |
|     | HOSTNAME=localhost.localdomain |
|     |     |
  2. 2. Modify the <span>/etc/sysconfig/network-script/ifcfg-eth0</span> file 
    |     |     |
| --- | --- |
|     | # Enable ipv6 address on boot |
|     | IPV6INIT=yes |
  3. 3. Restart the network interface and test

Static Address

A static address is configured by adding static IP settings in the <span>ifcfg-<interface></span> file

  • • Edit the file

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

    • • Add IPv4 configuration 
      |     |     |
| --- | --- |
|     | DNS1=192.168.0.1 |
|     | IPADDR=192.168.1.188 |
|     | PREFIX=24 |

      Tips: To configure a static IP, modify <span>BOOTPROTO=static</span>

    • • Add IPv6 configuration 
      |     |     |
| --- | --- |
|     | IPV6INIT=yes |
|     | IPV6_AUTOCONF=no |
|     | IPV6_FAILURE_FATAL=no |
|     | IPV6ADDR=2001:250:250:250:250:250:250:222/64 |
|     | IPV6_DEFAULTGW=2001:250:250:250::1 |
  • • Common configuration for <span>ifcfg-ethX</span> file 
    |     |     |
| --- | --- |
|     | # Type |
|     | TYPE=Ethernet |
|     | # Associated interface name, must match interface |
|     | DEVICE=eth0 |
|     | # Name of the network connection |
|     | NAME=eth0 |
|     | # Unique identifier |
|     | UUID=b4701c26-8ea8-46a5-b738-1d4d0ca5b5a9 |
|     | # Automatically connect, whether to activate this interface on startup or restart |
|     | ONBOOT=yes |
|     | # Boot protocol, indicates how to obtain IP |
|     | ### static | none: use static method |
|     | ### dhcp: use DHCP protocol |
|     | BOOTPROTO=static |
|     |     |
|     | ## Configuration information IPv4 configuration |
|     | # DNS server |
|     | DNS1=192.168.0.1 |
|     | # IP address |
|     | IPADDR=192.168.1.188 |
|     | # CentOS subnet mask length: 24 --> 255.255.255.0 |
|     | # NETMASK=255.255.255.0 |
|     | PREFIX=24 |
|     | # Default gateway |
|     | GATEWAY=192.168.1.1 |
|     | # IP2, IP3 ... |
|     | IPADDR2=192.168.2.23 |
|     | PREFIX2=24 |
|     | GATEWAY2=192.168.2.1 |
|     | # Disable device if ipv4 configuration fails |
|     | IPV4_FAILURE_FATAL=no |
|     | # Whether to set this interface as the default route for ipv4 |
|     | DEFROUTE=yes |
|     |     |
|     | # Whether to use IPV6 address: yes to use; no to disable |
|     | IPV6INIT=yes |
|     | # Whether to connect automatically yes for automatic, no for manual |
|     | IPV6_AUTOCONF=yes |
|     | # Whether to set this interface as the default route for ipv6 |
|     | IPV6_DEFROUTE=yes |
|     | # Disable device if ipv6 configuration fails |
|     | IPV6_FAILURE_FATAL=no |
|     | IPV6_ADDR_GEN_MODE="stable-privacy" |
|     |     |
|     | # Address ipv6 configuration information, if not using ipv6, this can be omitted |
|     | IPV6_PEERDNS=yes |
|     | IPV6_PEERROUTES=yes |
|     | IPV6_PRIVACY=no |

Tips:

  • • TYPE, BOOTPROTO, NAME, DEVICE, ONBOOT, IPV6INIT must exist;
  • • DNS1, IPADDR, GATEWAY, PREFIX/NETMASK are required for static IP configuration;

Temporary Address

A temporary address refers to a configuration that becomes invalid after a system reboot or network interface restart;

Common Network Configuration Commands

Configure IPv4

  1. 1. ifconfig configuration
  • • Configure temporary ipv4 address
  1. 1. ifconfig eth0 192.168.5.18 [up|down]
  2. 2. ip addr add 192.168.5.18/24 dev eth0
  • • Configure gateway

    route add -host 192.168.5.18 gw 192.168.5.1 dev eth0

    1. 1. ip route add default via 192.168.5.1

    Configure IPv6

    1. 1. Check ipv6 module
    • • Check if the ipv6 module is loaded

      lsmod | grep ipv6

    • • If not loaded, execute this command to load it

      modprobe ipv6

  • 2. Configuration
    • • Configure temporary ipv6 address

      ifconfig eth0 inet6 add IPV6ADDR

    • • Configure ipv6 gateway route [add|del] [-net|-host] [network or host][netmask mask] [gw default-ip] [dev interface name] route [add|del] default [gw nexthop]

      route -A inet6 add default gw IPV6GATEWAY dev ethX

    • • Example 
      |     |     |
| --- | --- |
|     | ifconfig eth0 inet6 add 2001:250:250:250:250:250:250:222/64 |
|     | route -A inet6 add default gw 2001:250:250:250::1 dev eth0 |

    Restart Network Interface

    • • CentOS 7

      systemctl restart network

    • • CentOS 6

      service network restart

    Testing

    • • ping

      ping | ping6 [-I interface] address

      • • IPv4 Test <span>ping [-I eth0] address</span>
        • • ping 192.168.5.18
      • • IPv6 Test <span>ping6 [-I eth0] address</span>

        Tips: You can also use the command <span>ifconfig</span> to view IPV6 address information; the system will automatically assign a local link address starting with “fe80:” as well as a globally unique IPv6 address that we manually configure.

        • • ping6 2001:250:250:250:250:250:250:222

    Link: https://www.cnblogs.com/librarookie/p/16288388.html

    (Copyright belongs to the original author, please delete if infringing)

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