I have a linux server that needs to get some routing. I'm fairly new at this and i don't find any clear source on google.

The setup should be simple:
All traffic to a server on ip should be sent over interface 3. All other interfaces don't matter at the moment.

Here you have the output for route -n

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface   U     0      0        0 eth0   U     0      0        0 eth1   U     0      0        0 eth2   U     0      0        0 eth3   U     0      0        0 eth4     U     1002   0        0 eth0         UG    0      0        0 eth0
  • 1
    Are you using the old fashioned ifconfig and route command or the modern ip commands? (old ones would be something like route add -host GW eth3_ip) – Hennes Mar 29 '13 at 13:48
  • i don't know, i guess the old ones, how can i check that? – Frederiek Mar 29 '13 at 13:58


ip route add dev eth3

| improve this answer | |
  • 3
    Just a note: to permanently keep this configuration make sure you add it to /etc/rc.local or your distro's equivalent. It won't persist between reboots. – LawrenceC Mar 29 '13 at 16:32
  • 2
    I tried this same format for mapping an IP to the wlan0 on Ubuntu 14.04 and got RTNETLINK answers: Invalid argument I had to remove the /** from the IP so I ended up with: sudo ip route add dev wlan0 -- thought I'd mention that in case anyone else ran into this issue. Thank you for your answer ultrasawblade, it was helpful. – mason81 Jul 10 '15 at 14:54
  • 4
    Do not forget via <gateway_ip> if the target IP is not directly reachable! – calandoa Dec 4 '17 at 15:00
  • How would I add another entry saying "use this interface for all other destination IPs"? – holzkohlengrill Jul 29 at 12:51
  • That's called setting a default gateway and is done with ip route add default via $ROUTER_IP dev $INTERFACE. – LawrenceC Jul 29 at 15:57

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.