https://bugs.kde.org/show_bug.cgi?id=520453
Bug ID: 520453
Summary: kdeconnectd breaks LAN mDNS by publishing addresses
for virtual bridge interfaces
Classification: Applications
Product: kdeconnect
Version First 25.12.3
Reported In:
Platform: Other
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: common
Assignee: [email protected]
Reporter: [email protected]
CC: [email protected]
Target Milestone: ---
DESCRIPTION
kdeconnectd publishes addresses for virtual bridge interfaces, such as virbr0,
in mDNS records advertised on the physical LAN interface. This breaks
connectivity between devices on my network because mycomputer.local sometimes
resolves to the virtual bridge address instead of the LAN address. The virtual
bridge address is not routable from other devices on the LAN.
In my case:
- Physical LAN interface: enp14s0, address 192.168.1.203
- Virtual bridge interface: virbr0, address 192.168.123.1
- Hostname: mycomputer.local
STEPS TO REPRODUCE
1. Have kdeconnectd running with LanLinkProvider enabled on a machine that also
has a virtual bridge interface, for example virbr0.
2. Ensure the machine also has a real LAN interface with a routable address,
for example enp14s0 with 192.168.1.203.
3. Browse KDE Connect mDNS records:
avahi-browse -rt _kdeconnect._udp
4. Resolve the host:
avahi-resolve -4 -n mycomputer.local
OBSERVED RESULT
kdeconnectd advertises the virtual bridge address as the address for
mycomputer.local.
Example output from avahi-browse:
= enp14s0 IPv6 _7c4a142c_7004_4438_a5c7_dfceb096a82e_ _kdeconnect._udp local
hostname = [mycomputer.local]
address = [192.168.123.1]
port = [1716]
txt = ["id=_7c4a142c_7004_4438_a5c7_dfceb096a82e_" "name=mycomputer"
"type=desktop" "protocol=8"]
The same service also advertises the correct LAN address on IPv4:
= enp14s0 IPv4 _7c4a142c_7004_4438_a5c7_dfceb096a82e_ _kdeconnect._udp local
hostname = [mycomputer.local]
address = [192.168.1.203]
port = [1716]
After this, mycomputer.local may resolve to the wrong address:
mycomputer.local 192.168.123.1
That address is not reachable from other LAN devices, so connections to
mycomputer.local fail intermittently or consistently depending on which mDNS
answer is used.
EXPECTED RESULT
kdeconnectd should not advertise addresses from virtual bridge interfaces as
the hostname address on the physical LAN.
For mDNS records sent on enp14s0, kdeconnectd should advertise the reachable
LAN address, e.g. 192.168.1.203, and not 192.168.123.1 from virbr0.
SOFTWARE/OS VERSIONS
KDE Connect: 25.12.3
Ubuntu 26.04 LTS (Wayland)
KDE Frameworks: 6.24.0
Qt: Using 6.10.2 and built against 6.10.2
Unknown/Default
Build ABI: x86_64-little_endian-lp64
Kernel: linux 7.0.2-070002-generic
ADDITIONAL INFORMATION
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