First principles

Using ifconfig

Show interface configuration

$ ifconfig eno1
eno1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.1.79  netmask 255.255.255.0  broadcast 192.168.1.255
        inet6 fe80::a6a5:87ad:cb7a:6cad  prefixlen 64  scopeid 0x20<link>
        ether 50:eb:f6:3f:27:61  txqueuelen 1000  (Ethernet)
        RX packets 137223  bytes 104941638 (104.9 MB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 91146  bytes 22484489 (22.4 MB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 16  memory 0xa1400000-a1420000  

Show All interfaces

$ ifconfig
br0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.2.1  netmask 255.255.255.0  broadcast 192.168.2.255
        ether 92:51:fc:1b:36:38  txqueuelen 1000  (Ethernet)
        RX packets 277  bytes 28650 (28.6 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 899  bytes 129148 (129.1 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

br-b737ea16f9fc: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 172.25.0.1  netmask 255.255.0.0  broadcast 172.25.255.255
        ether 02:42:79:64:bc:e2  txqueuelen 0  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

docker0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 172.17.0.1  netmask 255.255.0.0  broadcast 172.17.255.255
        ether 02:42:db:62:09:42  txqueuelen 0  (Ethernet)
.....

Add ip alias

$ ifconfig eth0:1 10.10.20.218 netmask 255.255.255.0 broadcast 10.10.20.255

Using ip

ip Usage

ip link show

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
    link/ether 50:eb:f6:3f:27:61 brd ff:ff:ff:ff:ff:ff
    altname enp0s31f6
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default qlen 1000
    link/ether 52:54:00:1f:16:1e brd ff:ff:ff:ff:ff:ff
4: br-b737ea16f9fc: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default 
    link/ether 02:42:72:e2:a7:bb brd ff:ff:ff:ff:ff:ff
5: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default 
    link/ether 02:42:25:da:f1:ee brd ff:ff:ff:ff:ff:ff

ip address show\

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 50:eb:f6:3f:27:61 brd ff:ff:ff:ff:ff:ff
    altname enp0s31f6
    inet 192.168.1.80/24 brd 192.168.1.255 scope global eno1
       valid_lft forever preferred_lft forever
    inet 172.14.0.2/24 brd 172.14.0.255 scope global eno1
       valid_lft forever preferred_lft forever
    inet6 fe80::52eb:f6ff:fe3f:2761/64 scope link 
       valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 52:54:00:1f:16:1e brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
4: br-b737ea16f9fc: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:72:e2:a7:bb brd ff:ff:ff:ff:ff:ff
    inet 172.25.0.1/16 brd 172.25.255.255 scope global br-b737ea16f9fc
       valid_lft forever preferred_lft forever
5: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:25:da:f1:ee brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0

add ip alias

$ ip a add 192.168.178.2/24 dev eth0