CentOS7 basic network configuration

Basic network configuration

NIC configuration parameters

• /etc/sysconfig/network-scipts/ifcfg-IFACE
• TYPE = interface type, there are common Ethernet, Bridge
• NAME=ens33
• DEVICE = device name
• ONBOOT = whether to activate the boot from the network interface card (yes | no)
• UUID = uniquely identifies the device
• IPV6INIT = whether to initialize IPv6
• BOOTPROTO = activated when the interface using what protocol to configure this interface attributes; DHCP (automatically assigned), bootp (automatically assigned), static (Static), none (static)
• IPADDR = IPv4 address
• PREFIX = mask length
• GATEWAY = default gateway
• DEFROUTE = is the default route using the interface
• First DNS server DNS1 =
• Alternate DNS server DNS2 =
• DOMAIN = DNS search domains
• USERCTL = normal user to control whether to allow the device
• If PEERDNS = dhcp BOOTPROTO value, whether to allow allocation dhcp dns dns specify manually directed pointing cover
• NM_CONTROLLED = whether to use NetworkManager service control interface

• HWADDR = MAC address of the device

  Set non-default routing

• /etc/sysconfig/network-scripts/route-IFACE
  • 1) a route entry in every row
    TARGET via GW
    Example:172.20.2.0/24 via 172.20.1.253

  • 2) a routing entry every third row represents a number #

        ADDRESS#=TARGET
        NETMASK#=MASK
    GATEWAY#=NEXTHOP
        ```
    
    示例：
        ```
    ADDRESS0=172.20.2.0
    NETMASK0=255.255.255.0
    GATEWAY0=172.20.1.254

A plurality of address interface configuration:

• 1) Use ifconfig

  ifconfig IFACE_LABEL ADDRESS NETMASK
  ifconfig ens33:1 172.20.2.11/24

• 2) Use ip

  ip addr add IFADDR dev IFACE label NAME
  ip addr add 172.20.3.11/24 dev ens33 label ens33:2

• 3) using a configuration file

  DEVICE=ens33:1
  BOOTPROTO选项只能为静态
  static none

• 4) Use nmcli command ( not recommended ).

  nmcli connection modify ens37 +ipv4.addresses "172.20.3.121/24"
  nmcli con down ens37
  nmcli con up ens37