Bug 427310

Summary: device discovery not working in ipv6-only network
Product: [Applications] kdeconnect Reporter: Daniel <daniel-other+kdebug>
Component: commonAssignee: Albert Vaca Cintora <albertvaka>
Status: REPORTED ---    
Severity: normal CC: sandro.jaeckel, thiago
Priority: NOR    
Version First Reported In: unspecified   
Target Milestone: ---   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description Daniel 2020-10-03 21:02:18 UTC 
SUMMARY
Currently, device discovery seems to only work in an network with ipv4, probably due to the broadcast address used in lanlinkprovider.


STEPS TO REPRODUCE
1. Have a ipv6-only network.
2. Have two kdeconnect-devices.

OBSERVED RESULT
They won't automatically discover each other. Only if you add one using a hostname, it works.

EXPECTED RESULT
Device discovery should also work in an ipv6-only network. I've tested it with multiple devices and am quite sure this isn't a network configuration mistake causing this bug.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 5.19.5
KDE Frameworks Version: 5.74.0
Qt Version: 5.15.1
Kernel Version: 5.8.13-arch1-1
OS Type: 64-bit
Comment 1 Daniel 2020-10-17 22:02:15 UTC 
The correct IPv6 equivalent of IPv4 broadcast is this multicast address: ff02::1%wlan0, where wlan0 is the interface, of which the local devices should be discovered.
Comment 2 Thiago Macieira 2021-03-30 22:12:45 UTC 
(In reply to Daniel from comment #1)
> The correct IPv6 equivalent of IPv4 broadcast is this multicast address:
> ff02::1%wlan0, where wlan0 is the interface, of which the local devices
> should be discovered.

Do not ever use ff02::1. Get a multicast address for KDE Connect instead.
Comment 3 Sandro 2025-06-25 18:53:48 UTC 
Do you have avahi enabled for ipv6? This is by default not the case because it makes many applications run into timeouts eg. printing which then takes an unnecessarily long amount of time.
Comment 4 Sandro 2025-06-25 22:38:25 UTC 
I just tested this with avahi mdns6 enabled. In `avahi-browse -ar` I see my phone but neither of my two devices can see the other. I am on Plasma 7.4.1.