Thanks. Your Google-fu is better than mine; my attempts only turned up much older results like "dhclient -r" or restarting systemd-networkd. The command you listed only works for systemd >= 244 apparently (since Ubuntu 20.04) and even still many newer search results still don't mention networkctl renew!

On Tue, Feb 13, 2024 at 9:42 AM Gilbert Detillieux <Gilbert.Detillieux@umanitoba.ca> wrote:
The answer, of course, depends on what distro and vintage, as this has
changed over time...

https://www.google.com/search?q=debian+ubuntu+force+dhcp+renewal

For most modern, systemd-based distros, you would likely use something
like this:

        networkctl renew interface-name

Restarting systemd-networkd would also work, but as you pointed out,
that's more extreme than necessary.

Gilbert

On 2024-02-13 8:53 a.m., Kevin McGregor wrote:
> Is there a way to force the DHCP client on Debian/Ubuntu to renew its
> lease ahead of time? For example, if the lease duration is a week, but
> you want the client to refresh the list of DNS servers immediately.
>
> Will "netplan apply" do it? Or "systemctl restart systemd-networkd"?
> That seems extreme; I don't want a network/service interruption --
> things like IP address/netmask/gateway won't change in the case I'm
> thinking of but other configuration details may need updating. Mind you,
> I have little idea what all systemd-networkd is responsible for.
>
> In Windows, for example, you'd run "ipconfig /renew". Is there an
> equivalent for Debian/Ubuntu?

--
Gilbert Detillieux          E-mail: Gilbert.Detillieux@umanitoba.ca
Computer Science            Web:    http://www.cs.umanitoba.ca/~gedetil/
University of Manitoba      Phone:  204-474-8161
Winnipeg MB CANADA  R3T 2N2
For best CS dept. service, contact <cs-support@lists.umanitoba.ca>.