ip
Table of Contents
1. Quick commands
ip -br -c [subcommand] # brief and colorized output
2. ip address
2.1. Output explanation
<BROADCAST,MULTICAST,UP,LOWER_UP>
: Interface state.- Broadcast & Multicast capable
- Interface is enabled
(UP)
- Physical layer is connected
(LOWER_UP)
mtu
: Maximum transmission unit (MTU) for the interface. (Default is 1500 bytes)qdisc
: The queueing approach being used by the interface.noqueue
: Send immediatelynoop
: Drop all
state
: Another indication of the operational state of an interface.UP
andDOWN
UNKNOWN
: Interface is up and operational, but nothing is connected.
group
: Interfaces can be grouped together on Linux to allow common attributes or commands. Usuallydefault
. Other usecase, eg. VM host system with 2 interfaces for management and 8 for data traffic. Group them intomgmt
anddata
groups.qlen
: Eg. 1000 – The interface has a 1000 packet queue. The 1001st packet would be dropped.inet:scope
:global
means globally reachable. Others can belink
andhost
inet:dynamic
: DHCP was used. Leased info invalid_lft
3. Other ip commands
ip link
: shows interfaces, can make changes to interfacesip neigh
: ARP table.ip route
: Routing table.src
attribute is to specify source ip in multihomed setups.ip route get
: Tells you which path will take (TODO)