custom firewall / iptables LOG / librespot

Dear All,

I am running a custom firewall rules.v4 with currently LibreELEC-RPi4.aarch64-13.0-nightly-20251126-257c8e7. Unfortunately, my custom iptables firewall is a bit to strict to let librespot be detectable by spotify. I want to debug the dropped packets by LOG statements like

-A INPUT -p udp -j LOG --log-level warning --log-prefix "UDP DROP:"

Unfortunately, I do not get any iptables LOG messages in dmesg, journalctl -k, or kodi.log.

How can I get the iptables LOG messages?

If I flush all firewall rules, librespot is detectable, with my custom firewall it is not detectable anymore. Any hints here? Which ports need to be open?

Thanks in advance for your help.

Thanks for your advise. implemented both suggestions. After a reboot the module xt_LOG is loaded:

I successfully got some iptables LOG messages in journalctl -k
and can now start to debug my firewall. Thanks.

With mlae's advices I could nail down my librespot problem:

In /storage/.kodi/userdata/addon_data/service.librespot/settings.xml I defined the zeroconf-port as follows:

<settings version="2"> 
   <setting id="name">Librespot@{7777}</setting> 
   <setting id="dnd_kodi" default="true">false</setting> 
   <setting id="backend" default="true" /> 
   <setting id="player" default="true" /> 
   <setting id="alsa_device" default="true">hw:2,0</setting> 
   <setting id="options" default="true">--zeroconf-port 55555</setting> 
</settings>

However, the option for zeroconf-port seems not to be used. After a reboot a

grep -i "librespot" /storage/.kodi/temp/kodi.log | tail -n 100

still shows a random port for librespot's event handler listening on port and not the specified 55555:

2025-11-28 11:25:36.831 T:1948     info <general>: Librespot: Event handler listening on port 52239

What are I am doing wrongly to prefefine the zeroconf-port of librespot?

The version of librespot is librespot 12.80.4.2
/ 0.8.0 049eb6e (Built on 2025-11-11, Build ID: NtYMPwJe, Profile: release).

Thanks in advance.

Quote

12.80.4.3 (coming soon) implements an explicit zeroconf port parameter

Whow, the release was faster than I expected:

LibreELEC-RPi4.aarch64-13.0-nightly-20251128-85c6ad7

is implementing the improvement librespot: Add setting for zerconf port #10643 .

And even better, I got it working in conjunction with my custom firewall rules.ip4:

The trick is to manually edit the setttings.xml file

/storage/.kodi/userdata/addon_data/service.librespot/settings.xml

as follows

<settings version="2">
    <setting id="name" default="true">Librespot@{}</setting>
    <setting id="dnd_kodi" default="true">false</setting>
    <setting id="backend" default="true" />
    <setting id="player" default="true" />
    <setting id="alsa_device" default="true">hw:2,0</setting>
    <setting id="zeroconf_fixed" default="true">true</setting>
    <setting id="zeroconf_port" default="50252">55555</setting>
</settings>

55555 is the zeroconf-port used in my custom firewall.

Thanks to the team for this great work!

Thanks for your feedback.

Quote

Should be possible with "standard" addon configuration. If not, it need to be fixed!

I x-checked again and can confirm that I got today a possibility to change the zeroconf port in the librespot configuration GUI:

I am quite sure that yesterday evening after upgrading to LibreELEC-RPi4.aarch64-13.0-nightly-20251128-85c6ad7 the last two lines were not shown. Yesterday evening the userdata settings.xml was still the old one from a very previous librespot version, see at the beginning of this thread.

/storage/.kodi/userdata/addon_data/service.librespot/settings.xml

Thanks again for your great support.