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Ifnot
Asked: 2021-02-01 01:52:14 +0800 CST

Ubuntu, specify interface for a single destination ip

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On Ubuntu, I have two interfaces eth0 (192.168.0.X) and wlan0 (192.168.1.X) both in DHCP with a gateway and internet.

How can I configure the system for using eth0 for all the trafic except one public ip adress routed on wlan0 by default ?

For example :

  • eth0 > all the trafic
  • wlan > just the trafic to 8.8.8.8

I got some responses using iptables but not involving destination whitelist like this.

ubuntu routing iptables

1 Answers

  1. Best Answer

    This is a simple scenario. You need to have two things:

    • Default gateway via eth0. Next hop will be 192.168.0.Y.
    • Static route for single host 8.8.8.8 via wlan0. Next hop will be 192.168.1.Y.

    No need to add any rule using iptables.

    You can add the default route and static route using these two commands respectively:

    ip route add default via 192.168.0.Y
ip route add 8.8.8.8/32 via 192.168.1.Y
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