Hi Mathieu,

> Glad you like it, and sorry for the late answer.

No worries! :)

>> substitute: guix substitute: warning: 10.0.0.5: connection failed: No route to host
>
> Once your laptop goes to sleep, Avahi should detect that the publish
> service is gone and remove it from the cache at
> /var/guix/discovery/publish.
>
> I'm having troubles reproducing it at home. Could you please run
> "avahi-browse -a" on your desktop, put your laptop to sleep, and check
> if the publish server disappears this way:
>
> --8<---------------cut here---------------start------------->8---
> - enp7s0f0 IPv6 guix-publish-cervin                           _guix_publish._tcp   local
> - enp7s0f0 IPv4 guix-publish-cervin                           _guix_publish._tcp   local
> --8<---------------cut here---------------end--------------->8---

To be sure we are on the same page, my desktop is the publisher, my
laptop is the client.

From my desktop:

--8<---------------cut here---------------start------------->8---
$ avahi-browse -a
+ enp7s0 IPv6 guix-publish-DESKTOP                                         _guix_publish._tcp   local
+ enp7s0 IPv4 guix-publish-DESKTOP                                         _guix_publish._tcp   local
+     lo IPv4 guix-publish-DESKTOP                                         _guix_publish._tcp   local
+ enp7s0 IPv6 LAPTOP                                                       _ssh._tcp            local
+ enp7s0 IPv6 DESKTOP                                                      _ssh._tcp            local
+ enp7s0 IPv4 LAPTOP                                                       _ssh._tcp            local
+ enp7s0 IPv4 DESKTOP                                                      _ssh._tcp            local
+     lo IPv4 DESKTOP                                                      _ssh._tcp            local
+ enp7s0 IPv6 LAPTOP [2a:81:b6:9b:6b:88]                                   _workstation._tcp    local
+ enp7s0 IPv6 DESKTOP [40:b0:76:0c:8d:47]                                  _workstation._tcp    local
+ enp7s0 IPv4 LAPTOP [2a:81:b6:9b:6b:88]                                   _workstation._tcp    local
+ enp7s0 IPv4 DESKTOP [40:b0:76:0c:8d:47]                                  _workstation._tcp    local
+     lo IPv4 DESKTOP [00:00:00:00:00:00]                                  _workstation._tcp    local
+ enp7s0 IPv6 LAPTOP                                                       _sftp-ssh._tcp       local
+ enp7s0 IPv6 DESKTOP                                                      _sftp-ssh._tcp       local
+ enp7s0 IPv4 LAPTOP                                                       _sftp-ssh._tcp       local
+ enp7s0 IPv4 DESKTOP                                                      _sftp-ssh._tcp       local
+     lo IPv4 DESKTOP                                                      _sftp-ssh._tcp       local
--8<---------------cut here---------------end--------------->8---

The output never changes, regardless of my laptop going to sleep or not.

You said "check if the publish server disappears" but why would it since it's
running on my desktop, which is not put to sleep?

Misunderstanding?  Forgive my ignorance about Avahi! :)

Cheers!

-- 
Pierre Neidhardt
https://ambrevar.xyz/