7

Systems:

  • Linux Mint 18.2 Cinnamon 64-bit (desktop mode, hands-on)

  • GNU/Linux Debian 9.2 Cinnamon 64-bit (headless mode, SSH)

Question:

How to release and renew IP address from the DHCP server (router) on these Linux systems?

1
  • If all you want to do is refresh your lease, you can use dhclient -v eth0 - replace eth0 with whatever your device is actually named
    – ivanivan
    Commented Nov 17, 2017 at 13:11

2 Answers 2

7

I have found there is the following program listening on the network on both of them:

dhclient

Quoting the man page:

-r     Release the current lease and stop the running DHCP client as  previously  recorded
       in  the  PID  file.  When shutdown via this method dhclient-script will be executed
       with the specific reason for calling the script set.  The client  normally  doesn't
       release  the  current  lease  as this is not required by the DHCP protocol but some
       cable ISPs require their clients to notify the server if they wish  to  release  an
       assigned IP address.

So, the solution for all interfaces would be:

sudo dhclient -r
sudo dhclient

Or, conveniently, for a specific interface, say eth0:

sudo dhclient -r eth0
sudo dhclient eth0

Of course, when SSH'ing into a server, you need to run both commands oneliner or write a script as per this answer.

2
  • It's a bit more complicated, because usually dhclient gets called automatically by some other part of your system, e.g. systemd. So if you start meddling manually, the part calling dhclient may get confused.
    – dirkt
    Commented Nov 17, 2017 at 12:36
  • 1
    @dirkt Ok, feel free to add a better answer. Commented Nov 17, 2017 at 12:40
-2

on ubuntu:

release:

sudo dhclient -r

renew:

sudo dhclient -1
1
  • 1
    Why is dhclient -1 better than just plain dhclient?  Please  do  not respond in  comments; edit  your answer to  make it clearer and  more complete. Commented Jul 6, 2019 at 21:20

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