ip linkLink
show the interface

ip link show 

ip link show ens33

bring the interface up

ip link set dev ens33 up




ip addrLink

ip addr

ip addr show ens33

Centos
 ip addr add 192.168.1.1/24 dev eth0




Private IP addresshttps://linuxhandbook.com/find-ip-address/

hostname -I

nmcli -p device show


Public IP addresshttps://www.tutorialspoint.com/find-my-public-ip-address-from-linux-command-line

curl ifconfig.me
ipinfo

https://ipinfo.io/account/home

curl -s ipinfo.io 

culr -s ipinfo.io/org


curl -s ipinfo.io/org/?token=xxxxxxxxxxxxxxx
Centos config file
dhcp

sudo more /etc/sysconfig/network-scripts/ifcfg-ens18


sudo vi /etc/sysconfig/network-scripts/ifcfg-ens18

BOOTPROTO=dhcp
DEFROUTE=yes
DEVICE=ens18
DHCPV6C=no
MTU=1500
NM_CONTROLLED=yes
ONBOOT=yes
PEERDNS=yes
TYPE=Ethernet
USERCTL=no


Static IP addressnetwork-scripts ifcfg-ens ifcfg-eth

sudo more /etc/sysconfig/network-scripts/ifcfg-ens18


sudo vi /etc/sysconfig/network-scripts/ifcfg-ens18



systemctl restart network.service
UbuntuConfig file

renderer: networkd

renderer: NetworkManager
( not installed by default )


Raspberry + dual IP addressdebian

more /etc/network/interfaces


root@boxed:/var/www/html# more /etc/network/interfaces
# interfaces(5) file used by ifup(8) and ifdown(8)

# Please note that this file is written to be used with dhcpcd
# For static IP, consult /etc/dhcpcd.conf and 'man dhcpcd.conf'

# Include files from /etc/network/interfaces.d:
source-directory /etc/network/interfaces.d

auto eth0
iface eth0 inet dhcp

auto eth0:1
allow-hotplug eth0:1
iface eth0 inet static
      address 192.168.226.101
      netmask 255.255.255.0
      gateway 192.168.226.1
      dns-maneservers 8.8.8.8




networkdnetplan ( ubuntu on AWS )
netplan
vi /etc/netplan/xx--installer-config.yaml
!!! all the files in the list will be used

sudo netplan apply
sudo netplan get   ( get the config information )


more /etc/netplan/10-installer-config.yaml
# This is the network config written by 'subiquity'
network:
  version: 2
  renderer: networkd
  ethernets:
    ens33:
      dhcp4: true
    ens34:
      dhcp4: no
      addresses: [10.1.4.10/24]
      gateway4: 10.1.4.2


bond or lag


. . . 
  bonds:
    bond0:
      addresses:
        - 10.0.0.1/24
      interfaces:
        - eno1
        - eno2
      parameters:
        mode: 802.3ad
        lacp-rate: slow
        transmit-hash-policy: layer3+4
        mii-monitor-interval: 1


vlan


  . . .
  vlans:
    bond0.100:
      id: 100
      link: bond0
      addresses:
        - 10.100.0.1/24



 netplan apply


Network Manager

DHCP
/etc/network/interfaces
auto eth1
  iface eth1 inet dhcp

sudo systemctl restart networking
Static


# The primary network interface
iface eth0 inet manual
auto pnet0
iface pnet0 inet static
    pre-up ip link set dev eth0 up
    address 192.168.0.115
    network 192.168.0.0
    netmask 255.255.255.0
    gateway 192.168.0.1
    dns-nameserver 8.8.8.8
    dns-search  example.com
    bridge_ports eth0
    bridge_stp off