Re: Flushing DNS caches items on clock change.

[Lennart Poettering <lennart@xxxxxxxxxxxxxx>]

On Mi, 30.08.23 18:06, Vishwanath Chandapur (vishwavtu@xxxxxxxxx) wrote:

> Hi,
>
> We are using systemd-resolved. We observed that on clock change,
> systemd-resolved is flushing all caches.
>
> By looking into the code we found that this is implemented primarily for
> DNSSEC.
>
> Is there any specific reason for flushing the other cache items like mDNS,
> LLMNR?

Usually things like clock jumps happen on system suspend/resume
cycles, VM migration and other VM management non-linearities. Quite
often this coincides with network connectivity changes, and hence we
should invalidate whatever information we collected so far about the
network.

Given this is redundant info we can reacquire this should not be an issue.

Lennart

--
Lennart Poettering, Berlin