ip-route-get

performs a route lookup and displays exactly which route the kernel would use

TLDR

Print route to destination

$ ip route get [1.1.1.1]

Print route from a specific source

$ ip route get [destination] from [source]

Print route for packets arriving on a specific interface

$ ip route get [destination] iif [eth0]

Print route forcing output through specific interface

$ ip route get [destination] oif [eth0]

Print route with Type of Service

$ ip route get [destination] tos [0x10]

Print route using VRF instance

$ ip route get [destination] vrf [myvrf]

Print route for a packet with a firewall mark (policy routing)

$ ip route get [destination] mark [0x1]

Show the matching FIB entry instead of the resolved route

$ ip route get fibmatch [destination]

Look up a route for a specific protocol and port

$ ip route get [destination] ipproto [tcp] dport [443]

Look up an IPv6 route

$ ip -6 route get [2606:4700:4700::1111]

ip route get [fibmatch] ADDRESS [from ADDRESS] [iif DEV] [oif DEV] [mark MARK] [tos TOS] [vrf NAME] [ipproto PROTOCOL] [sport NUMBER] [dport NUMBER] [connected]

DESCRIPTION

ip route get performs a route lookup and displays exactly which route the kernel would use for a given destination. This shows the complete route entry including gateway, interface, source address, and any other attributes.Unlike ip route list, which shows stored routes, ip route get queries the kernel's routing decision for a specific packet, accounting for policy routing rules and route selection algorithms. It is equivalent to sending a packet along this path, but no packets are actually sent. Without iif, the kernel resolves a route for locally generated output; with iif, it pretends a packet arrived on that interface and looks for a forwarding path.

PARAMETERS

fibmatch

Return the full FIB lookup matched route instead of the resolved destination entry

to ADDRESS

Destination address (the to keyword is optional)

from SOURCE

Source address for route lookup

iif DEVICE

Input interface (for forwarded packets)

oif DEVICE

Force output interface

tos, dsfield TOS

Type of Service value

vrf NAME

VRF instance name

mark MARK

Firewall mark (fwmark) value

ipproto PROTOCOL

IP protocol as seen by the route lookup

sport NUMBER, dport NUMBER

Source and destination port as seen by the route lookup

connected

If no from is given, redo the lookup with the source set to the preferred address from the first lookup

INSTALL

sudo apt install iproute2

sudo pacman -S iproute2

sudo apk add iproute2-minimal

sudo zypper install iproute2

brew install iproute2

nix profile install nixpkgs#iproute2

CAVEATS

The output reflects the current routing state, which may change dynamically. VRF lookups require the VRF to be configured. Mark-based lookups require matching policy rules. Using iif requires IP forwarding to be enabled, otherwise the lookup may fail.

HISTORY

ip route get is part of iproute2 and provides insight into the kernel's actual routing decisions, which can differ from the stored route table due to policy rules and route metrics.

RESOURCES

Source code · Documentation