Linux ip Command Examples
Intro
In a recent blog we explored using the ss command to replace netstat. The iproute2 package that provides ss also provides ip, which as the title of this blog suggests, replaces ifconfig and arp.
All of those old utilities are considered deprecated, so you really should get comfortable with the iproute2 replacements. They aren’t going away anytime soon, but utilities like ifconfig are already removed from the latest versions of modern Linux distros like Ubuntu.
So, let’s go through the common use cases of the deprecated utilities, and see how we can replicate or even improve on the functionality with ip.
List network interfaces and IP address
Old:
ifconfig -a
New:
ip addr
Short list of network interfaces
Old:
ifconfig -s
New:
ip link
Set an IP address manually
Old:
ifconfig eth0 10.0.0.140 netmask 255.255.255.0 broadcast 10.0.0.255
New:
ip addr add 10.0.0.140/24 dev eth0
Bring interfaces up or down
Old:
ifconfig eth0 up
ifconfig eth0 down
New:
ip link set eth0 up
ip link set eth0 down
Print out the ARP cache
Old:
arp
New:
ip neigh
Print out the route table
Old:
netstat -r
route
New:
ip route
Common Options
ip supports a few common options across command and objects to give you more info:
Show only IPv6 objects
ip -6 addr
Show only IPv4 objects
Here we’re using the maddr object, which are multicast addresses
ip -4 maddr
Show Statistics
ip -s link
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
RX: bytes packets errors dropped overrun mcast
656434 2906 0 0 0 0
TX: bytes packets errors dropped carrier collsns
656434 2906 0 0 0 0
Show Human Readable Statistics
ip -s link
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
RX: bytes packets errors dropped overrun mcast
656k 2.90k 0 0 0 0
TX: bytes packets errors dropped carrier collsns
656k 2.90k 0 0 0 0
Show Brief Output
ip -br link
lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP>
enp3s0 UP 11:22:33:44:55:66 <BROADCAST,MULTICAST,UP,LOWER_UP>
Taking it Further
Syntax Shortcuts
Technically, the command to list IP addresses is:
ip address show
However, the ip command accepts abbreviated directives much like common networking OS command line interpreters.
Likewise, we abbreviated ip neighbor show down to ip neigh. You can go even further with something like ip n s or just ip n.
More Objects and Commands
There’s a pattern:
ip $OBJECT $COMMAND
Both objects and commands can be abbreviated as mentioned above. There are a bunch of objects at your disposal, including familiar stuff we’ve already seen:
- address
- neighbor
- route
- rule
- tunnel
- tuntap
There’s also a bunch of esoteric stuff you can lookup in the man page. Most of the objects support add, delete, show, list (with the default usually being show) but some have different actions or require slightly different arguments. You can get more information on how to use a particular object with:
man ip $COMMAND
man ip neigh
man ip address
Summary
Well, there you have it, ip actually has a pretty consistent layout and a pretty good man page. I highly recommend going through it if you find yourself needing to do something not covered here. I do think this should be enough to get you started with ip, and feeling more confident about ditching ifconfig, route, and arp.