ip

IP queries

SubCommand	Tasks
addr	Display IP Addresses and property information (abbreviation of address)
`ip addr`	Show information for all addresses
`ip addr show dev em1`	Display information only for device em1
link	Manage and display the state of all network interfaces
`ip link`	Show information for all interfaces
`ip link show dev em1`	Display information only for device em1
`ip -s link`	Display interface statistics
route	Display and alter the routing table
`ip route`	List all of the route entries in the kernel
maddr	Manage and display multicast IP addresses
`ip maddr`	Display multicast information for all devices
`ip maddr show dev em1`	Display multicast information for device em1
neigh	Show neighbour objects; also known as the ARP table for IPv4
`ip neigh`	Display neighbour objects
`ip neigh show dev em1`	Show the ARP cache for device em1
help	Display a list of commands and arguments for each subcommand
`ip help`	Display ip commands and arguments
`ip addr help`	Display address commands and arguments
`ip link help`	Display link commands and arguments
`ip neigh help`	Display neighbour commands and arguments

SubCommand	Tasks
maddr add	Add a static link-layer multicast address
`ip maddr add 33:33:00:00:00:01 dev em1`	Add multicast address 33:33:00:00:00:01 to em1
maddr del	Delete a multicast address
`ip maddr del 33:33:00:00:00:01 dev em1`	Delete address 33:33:00:00:00:01 from em1

SubCommand	Tasks
addr add	Add an address
`ip addr add 192.168.1.1/24 dev em1`	Add address 192.168.1.1 with netmask 24 to device em1
addr del	Delete an address
`ip addr del 192.168.1.1/24 dev em1`	Remove address 192.168.1.1/24 from device em1

SubCommand	Tasks
link set	Alter the status of the interface
`ip link set em1 up`	Bring em1 online
`ip link set em1 down`	Bring em1 offline
`ip link set em1 mtu 9000`	Set the MTU on em1 to 9000
`ip link set em1 promisc on`	Enable promiscuous mode for em1

SubCommand	Tasks
route add	Add an entry to the routing table
`ip route add default via 192.168.1.1 dev em1`	Add a default route (for all addresses) via the local gateway 192.168.1.1 that can be reached on device em1
`ip route add 192.168.1.0/24 via 192.168.1.1`	Add a route to 192.168.1.0/24 via the gateway at 192.168.1.1
`ip route add 192.168.1.0/24 dev em1`	Add a route to 192.168.1.0/24 that can be reached on device em1
route delete	Delete a routing table entry
`ip route delete 192.168.1.0/24 via 192.168.1.1`	Delete the route for 192.168.1.0/24 via the gateway at 192.168.1.1
route replace	Replace, or add if not defined, a route
`ip route replace 192.168.1.0/24 dev em1`	Replace the defined route for 192.168.1.0/24 to use device em1
route get	Display the route an address will take
`ip route get 192.168.1.5`	Display the route taken for IP 192.168.1.5

SubCommand	Tasks
neigh add	Add an entry to the ARP Table
`ip neigh add 192.168.1.1 lladdr 1:2:3:4:5:6 dev em1`	Add address 192.168.1.1 with MAC 1:2:3:4:5:6 to em1
neigh del	Invalidate an entry
`ip neigh del 192.168.1.1 dev em1`	Invalidate the entry for 192.168.1.1 on em1
neigh replace	Replace, or adds if not defined, an entry to the ARP table
`ip neigh replace 192.168.1.1 lladdr 1:2:3:4:5:6 dev em1`	Replace the entry for address 192.168.1.1 to use MAC 1:2:3:4:5:6 on em1

Add name spaces:

ip netns add red
ip netns add blue

Then

> ip netns
red
blue

To execute an ip command inside the name space:

ip netns exec red ip link

or use shorter notation:

ip -n red link
ip -n red arp
ip -n red route