Home / ubuntu / Questions / 103171
In Process
Lorin Hochstein
Asked: 2012-02-11 12:48:44 +0800 CST

Editing network interfaces without system rebooting

  • 772

I'd like to make some changes to my networking configuration by editing my /etc/network/interfaces file. What's the cleanest way to make changes to this file and have them take effect, without having to reboot? Typically, I've been doing:

  1. Edit the file
  2. service networking restart

But I have the impression that this isn't the "right" way to make these kinds of changes.

networking network-manager

7 Answers

  1. Shut the network interface down using

    sudo ifdown eth0

    (replace eth0 with the interface you want to change) and bring it up again using

    sudo ifup eth0
    • 11

  2. In Ubuntu Server 16.04 and above you must use the ip command (man page) to flush the address before restarting networking, otherwise any address changes in the interfaces file will not take effect:

    $ sudo ip addr flush interface-name
$ sudo systemctl restart networking

    I got this answer from this helpful article

    • 11

  3. Stop all interfaces using 

    sudo /etc/init.d/networking stop

    Configure (edit) your interfaces as you wish, then

    Start them again

    sudo /etc/init.d/networking start

    There is no need to reboot.

    • 3

  4. Why don't you think it is the right way. Think, what can ubuntu do extra during booting? Ubuntu has a list of services that need to run during booting, each service has a list of consecutive command to start itself. Ubuntu just run networking service through /etc/init.d/networking script which contains some command that need to run network service. So if any change need to apply to your network then you have to restart your service and the way is recall your service's consecutive commands.

    • 1

  5. /etc/network/interfaces controls the ifupdown tools.

    So after making changes, you can just say eg sudo ifup eth0.

    • 1

  6. Actually none of these work. Tested on Ubuntu 16.10. these had no effect.

    • ifdown ens3 and ifup ens3
    • service network stop and start
    • service network reload
    • systemctl stop networking.service and then start again.

    Through all these the old dhcp ip came back and not the static. i wonder if this is intentional?

    • 0

  7. Try a flush between ifup and ifdown. This worked on Mendel (Google Coral), which is a Debian based.

    sudo ifdown eth0 && sudo ip addr flush eth0 && sudo ifup eth0

    Without the flush, the interface would restart without reading the config file.

    • 0