Hi Giovanni, Thank you for reporting this problem.
I was doing some research and it was reported upstream here: https://lore.kernel.org/regressions/[email protected]/ and was fixed in: commit 5189446ba995556eaa3755a6e875bc06675b88bd Author: Oscar Maes <[email protected]> Date: Wed Aug 27 08:23:21 2025 +0200 Subject: net: ipv4: fix regression in local-broadcast routes Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5189446ba995556eaa3755a6e875bc06675b88bd this landed in $ git describe --contains 5189446ba995556eaa3755a6e875bc06675b88bd v6.17-rc4~17^2 so its already in questing and resolute. I checked the backport situation: ubuntu-noble$ git log --grep "net: ipv4: fix incorrect MTU in broadcast routes" origin/master-next commit 79b7e9c6019572e2e3e441d9ac9a68612934df42 Author: Oscar Maes <[email protected]> Date: Wed Aug 27 08:23:21 2025 +0200 net: ipv4: fix regression in local-broadcast routes ubuntu-noble$ git describe --contains 79b7e9c6019572e2e3e441d9ac9a68612934df42 Ubuntu-6.8.0-103.103~2092 ubuntu-jammy$ git log --grep "net: ipv4: fix incorrect MTU in broadcast routes" origin/master-next commit 1636d4c7332490e9d12b295fde6f4e88f0e7a0f8 Author: Oscar Maes <[email protected]> Date: Wed Aug 27 08:23:21 2025 +0200 net: ipv4: fix regression in local-broadcast routes $ git describe --contains 1636d4c7332490e9d12b295fde6f4e88f0e7a0f8 Ubuntu-5.15.0-163.173~110 So jammy is already fix released, while this will be in the next noble SRU. Please hold tight for 6.8.0-103-generic. It is in -proposed right now if you want to try: Instructions to Install (On a noble system): 1) cat << EOF | sudo tee /etc/apt/sources.list.d/ubuntu-$(lsb_release -cs)-proposed.list # Enable Ubuntu proposed archive deb http://archive.ubuntu.com/ubuntu/ $(lsb_release -cs)-proposed main universe EOF 2) sudo apt update 3) sudo apt install linux-{image,modules,modules-extra,headers}-6.8.0-103-generic 4) sudo reboot 5) uname -rv 6.8.0-103-generic #103-Ubuntu SMP PREEMPT_DYNAMIC Tue Feb 10 13:34:59 UTC 2026 6) sudo rm /etc/apt/sources.list.d/ubuntu-$(lsb_release -cs)-proposed.list I tested it now, and it works. $ sudo tcpdump -n -i enp1s0 port 9 -e tcpdump: verbose output suppressed, use -v[v]... for full protocol decode listening on enp1s0, link-type EN10MB (Ethernet), snapshot length 262144 bytes 23:59:45.170723 52:54:00:5f:62:ec > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 144: 192.168.122.18.49769 > 255.255.255.255.9: UDP, length 102 ^C 1 packet captured 1 packet received by filter 0 packets dropped by kernel $ uname -rv 6.8.0-103-generic #103-Ubuntu SMP PREEMPT_DYNAMIC Tue Feb 10 13:34:59 UTC 2026 Thanks, Matthew -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2141584 Title: Sending wakeonlan magic packet from kernel 6.8.0-100-generic no longer works (UDP broadcast wrong destination address) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2141584/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
