Understanding ip command

Show IPv4 and IPv6 interfaces

$ ip -4 a
$ ip -6 a

Show interface ens4 details

$ ip a show ens4
$ ip a show dev ens4
$ ip a list ens4

Show only running interfaces

$ ip link ls up

Add the IP address to the interface

Add IP address to the interface

$ sudo ip address add 192.168.100.100/255.255.2550 dev ens4
$ sudo ip address add 192.168.100.100/24 dev ens4

Add broadcast address to the interface

$ sudo ip address add broadcast 192.168.100.255 dev ens4

Remove the IP address from the interface

Delete IP address from the interface

$ sudo ip address del 192.168.100.100/24 dev ens4

Flush all IP addresses from the private network

$ sudo ip -s -s a f 192.168.100.100/24

Change state of the interface

Make the interface down

$ sudo ip link set dev ens4 down

Make the interface up

$ sudo ip link set dev ens4 up

Change the MTU of the interface

$ sudo ip link set mtu 1500 dev ens4

Show neighbour / arp cache

$ sudo ip neighbor show

Add new ARP entry

$ sudo ip neighbor add 192.168.100.100 lladdr 42:01:0a:80:00:01 dev ens4 nud perm

nud states:

  • permanent – Entry is valid forever and can only be removed administratively.
  • noarp – Entry is valid, and can be removed when its lifetime expires
  • stale – Entry is valid but suspicious.
  • reachable – Entry is valid until the reachability timeout expires

Delete a ARP entry

$ sudo ip neighbor del 192.168.100.100 dev ens4

Change the state of the ARP entry

$ sudo ip neighbor change 192.168.100.100 dev ens4 nud reachable

Flush ARP entry

$ ip -s -s n flush 192.168.100.100

ip route

Show routing table

$ ip r list
$ ip route list

Display routing for 192.168.100.1/24

$ ip route list 192.168.100.1/24

Add new route

$ ip route add {NETWORK/MASK} via {GATEWAY}
$ ip route add 192.168.100.0/24 via 192.168.100.1

Delete route

$ ip route del default

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