On a Raspberry Pi Zero 2 W, when the network interface's Power Management is set to "on", the Pi occasionally fails to respond to mDNS multicast requests #7272
Description
Describe the bug
On a Raspberry Pi Zero 2 W, when the network interface's Power Management is set to "on", the Pi occasionally fails to respond to mDNS multicast requests (tcpdump on the Pi does not capture any mDNS multicast requests packets):
I apologize for not being sure where this issue should be reported.
I noticed others have experienced similar behavior on the forums (https://forums.raspberrypi.com/viewtopic.php?p=2332219&hilit=mdns#p2332219). Is this a bug in the Power Management mode, a feature that was intentionally omitted from the design of Power Management mode, or perhaps a bug in the system, hardware, or firmware?
If there is no short-term fix available for this bug, should we consider adding a note to line 98 of raspberry/documentation/asciidoc/computers/remote-access/find-your-ip-address.adoc to prevent new users from encountering the same issue?
Steps to reproduce the behaviour
a Pi zero 2w with raspberrypiOS(64bit without Desktop),
run iwconfig wlan0 | grep "Power Management"
if Power Management is off ,open it by iwconfig wlan0 power on
Before pinging or using SSH, ensure that LLMNR (a feature that allows device discovery on the local network) is enabled on Windows, or you can try testing on Linux (the results should be the same).
then try to ping this Pi's hostname (or ssh) in the same LAN,such as ssh User@hostname or ping hostname
Device (s)
Raspberry Pi Zero 2 W
System
$ cat /etc/rpi-issue
Raspberry Pi reference 2025-12-04
Generated using pi-gen, https://github.com/RPi-Distro/pi-gen, 4997bf4e4e49bc3305eb182a4a08bd023529da04, stage2
$ vcgencmd version
Aug 20 2025 17:04:09
Copyright (c) 2012 Broadcom
version cd866525580337c0aee4b25880e1f5f9f674fb24 (clean) (release) (start)
$ uname -a
Linux Lab05568 6.12.62+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.12.62-1+rpt1 (2025-12-18) aarch64 GNU/Linux
Logs
Windows ssh login process:
ssh rb
ssh: Could not resolve hostname RaspBerryPi.local: \344\270\215\347\237\245\351\201\223\350\277\231\346\240\267\347\232\204\344\270\273\346\234\272\343\200\202
PS C:\Users\User> ping 10.174.102.9
Pinging 10.174.102.9 with 32 bytes of data:
Reply from 10.174.102.9: bytes=32 time=219ms TTL=60
Reply from 10.174.102.9: bytes=32 time=134ms TTL=60
Reply from 10.174.102.9: bytes=32 time=49ms TTL=60
10.174.102.9 的 Ping 统计信息:
数据包: 已发送 = 3，已接收 = 3，丢失 = 0 (0% 丢失)，
往返行程的估计时间(以毫秒为单位):
最短 = 49ms，最长 = 219ms，平均 = 134ms
Control-C
PS C:\Users\User> ssh rb
Enter passphrase for key 'id_ed25519':
Linux RaspBerryPi 6.12.62+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.12.62-1+rpt1 (2025-12-18) aarch64
The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.
Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Thu Mar 12 11:22:56 2026 from 240e:424:260:3893:fdff:9762:66d4:7fcf
user@RaspBerryPi:~ $
Prove that the mDNS service has started normally.:
$ journalctl -b | grep -in mDNS
579:Mar 12 11:27:43 Lab05568 systemd[1]: Listening on avahi-daemon.socket - Avahi mDNS/DNS-SD Stack Activation Socket.
590:Mar 12 11:27:43 Lab05568 systemd[1]: Starting avahi-daemon.service - Avahi mDNS/DNS-SD Stack...
623:Mar 12 11:27:43 Lab05568 systemd[1]: Started avahi-daemon.service - Avahi mDNS/DNS-SD Stack.
624:Mar 12 11:27:43 Lab05568 avahi-daemon[521]: Joining mDNS multicast group on interface lo.IPv6 with address ::1.
625:Mar 12 11:27:43 Lab05568 avahi-daemon[521]: New relevant interface lo.IPv6 for mDNS.
626:Mar 12 11:27:43 Lab05568 avahi-daemon[521]: Joining mDNS multicast group on interface lo.IPv4 with address 127.0.0.1.
627:Mar 12 11:27:43 Lab05568 avahi-daemon[521]: New relevant interface lo.IPv4 for mDNS.
791:Mar 12 11:27:58 Lab05568 avahi-daemon[521]: Joining mDNS multicast group on interface wlan0.IPv4 with address 10.174.142.9.
792:Mar 12 11:27:58 Lab05568 avahi-daemon[521]: New relevant interface wlan0.IPv4 for mDNS.
816:Mar 12 11:27:59 Lab05568 avahi-daemon[521]: Joining mDNS multicast group on interface wlan0.IPv6 with address fe80::8aa2:9eff:fe58:a247.
817:Mar 12 11:27:59 Lab05568 avahi-daemon[521]: New relevant interface wlan0.IPv6 for mDNS.
822:Mar 12 11:28:01 Lab05568 avahi-daemon[521]: Leaving mDNS multicast group on interface wlan0.IPv6 with address fe80::8aa2:9eff:fe58:a247.
823:Mar 12 11:28:01 Lab05568 avahi-daemon[521]: Joining mDNS multicast group on interface wlan0.IPv6 with address 240e:424:260:3893:8aa2:9eff:fe58:a247.
windows_dump_when_try_ssh_login_pcapng.txt__
Additional context
No response