[systemd-devel] Question about sysctl persistence

[Lennart Poettering]

On Fr, 18.04.25 00:35, EpicTux123 (EpicTux123 at proton.me) wrote:

> Hello there.
>
> I had the following file in my system:
>
> /etc/sysctl.d/90-custom-mtu-probing.conf
> net.ipv4.tcp_mtu_probing=1
>
> I deleted that file and rebooted my system.
> But the "net.ipv4.tcp_mtu_probing" value is still "1", even though
> its default is "0".

This looks as if something else in your system is fiddling with that
setting.

To check if anything is doing that via "systemd-sysctl", you can run
"/usr/lib/systemd/systemd-sysctl --tldr".

Other tools that manage variable like that are usually networking and
routing daemons. (Not systemd-networkd though, it doesn#t manager that one).

Lennart

--
Lennart Poettering, Berlin