Linux ip command

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The ip command from the iproute2 tool collection is used under Linux to configure network addresses. It replaces the ifconfig command from the obsolete net-tools. This article shows the most important parameters of the ip command using a few examples.

Comparison table ip versus ifconfig

The table shows important commands for network configuration and compares the syntax of the ip and ifconfig commands:

Purpose iproute2 command iproute2 command (short version) net-tools command
Show link status ip link show ip l ifconfig
Show link status including statistics
(RX/TX bytes, errors, ...) 		ip -statistics link show ip -s l ifconfig
Show IP address ip addr show ip a ifconfig -a
Set IP address ip addr add IP/NETMASK dev DEVICE ip a a IP/NETMASK dev DEVICE ifconfig DEVICE IP/NETMASK
Delete IP address ip addr del IP/NETMASK dev DEVICE ip a d IP/NETMASK dev DEVICE
Delete all IP addresses of a device ip addr flush dev DEVICE ip a f dev DEVICE
Show routing table ip route show ip r route -n
Set standard gateway ip route add default via IP ip r a default via IP route add default gw IP DEVICE
Show ARP cache ip neigh show ip n arp -na
Show connections ss --tcp --all --processes --extended --numeric ss -tapen netstat -tapen

Examples

The following outputs show some examples of iproute2 commands.

ip help

$ ip help
Usage: ip [ OPTIONS ] OBJECT { COMMAND | help }
       ip [ -force ] -batch filename
where  OBJECT := { link | addr | addrlabel | route | rule | neigh | ntable |
                   tunnel | tuntap | maddr | mroute | mrule | monitor | xfrm |
                   netns }
       OPTIONS := { -V[ersion] | -s[tatistics] | -d[etails] | -r[esolve] |
                    -f[amily] { inet | inet6 | ipx | dnet | link } |
                    -l[oops] { maximum-addr-flush-attempts } |
                    -o[neline] | -t[imestamp] | -b[atch] [filename] |
                    -rc[vbuf] [size]}

ip link show

$ ip link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 08:00:27:66:72:e1 brd ff:ff:ff:ff:ff:ff

ip -statistics link show

$ ip link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    RX: bytes  packets  errors  dropped overrun mcast   
    2073916    4895     0       0       0       0      
    TX: bytes  packets  errors  dropped carrier collsns 
    2073916    4895     0       0       0       0      
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 08:00:27:66:72:e1 brd ff:ff:ff:ff:ff:ff
    RX: bytes  packets  errors  dropped overrun mcast   
    1716782262 1369751  0       0       0       0      
    TX: bytes  packets  errors  dropped carrier collsns 
    308636400  1172428  0       0       0       0

ip addr show

$ ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 08:00:27:66:72:e1 brd ff:ff:ff:ff:ff:ff
    inet 10.1.102.59/24 brd 10.1.102.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::a00:27ff:fe66:72e1/64 scope link 
       valid_lft forever preferred_lft forever

ip addr add IP/NETMASK dev DEVICE

$ sudo ip addr add 10.1.102.60/24 dev eth0
$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 08:00:27:66:72:e1 brd ff:ff:ff:ff:ff:ff
    inet 10.1.102.59/24 brd 10.1.102.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet 10.1.102.60/24 scope global secondary eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::a00:27ff:fe66:72e1/64 scope link 
       valid_lft forever preferred_lft forever

ip addr del IP/NETMASK dev DEVICE

$ sudo ip addr del 10.1.102.60/24 dev eth0
$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 08:00:27:15:17:5e brd ff:ff:ff:ff:ff:ff
    inet 10.1.102.54/24 brd 10.1.102.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::a00:27ff:fe15:175e/64 scope link 
       valid_lft forever preferred_lft forever

ip addr flush dev DEVICE

$ sudo ip addr flush dev eth0
$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 08:00:27:15:17:5e brd ff:ff:ff:ff:ff:ff

ip route show

$ ip route show
default via 10.1.102.1 dev eth0  metric 100 
10.1.102.0/24 dev eth0  proto kernel  scope link  src 10.1.102.59

ip route add default via IP

$ sudo ip route add d via 10.1.102.1

ip neigh show

$ ip neigh show
10.1.102.101 dev eth0 lladdr f0:de:f1:f3:17:88 REACHABLE
10.1.102.1 dev eth0 lladdr 00:0c:42:97:79:63 REACHABLE

Further information

Foto Werner Fischer.jpg

Author: Werner Fischer

Werner Fischer, working in the Knowledge Transfer team at Thomas-Krenn, completed his studies of Computer and Media Security at FH Hagenberg in Austria. He is a regular speaker at many conferences like LinuxTag, OSMC, OSDC, LinuxCon, and author for various IT magazines. In his spare time he enjoys playing the piano and training for a good result at the annual Linz marathon relay.


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