Hi, it seems systemd-networkd of the Buster distribution does not work reliable on some of my systems. Can you help me to further analyze the problem in front of bug creation?
Short summary: If an interface uses static addresses and the cable is unplugged and plugged in again, the interface does not go up anymore. Detailed summary: Architecture: amd64 Kernel: Linux 4.19.0-6-amd64 #1 SMP Debian 4.19.67-2 (2019-08-28) x86_64 GNU/Linux systemd: Version: 241-7~deb10u1 The system contains two ethernet links "enp1s0" and "eno1". The kernel module used for this interfaces is "igb". === Oct 08 09:38:44 sb-0001c0237244 kernel: igb: Intel(R) Gigabit Ethernet Network Driver - version 5.4.0-k Oct 08 09:38:44 sb-0001c0237244 kernel: igb: Copyright (c) 2007-2014 Intel Corporation. Oct 08 09:38:44 sb-0001c0237244 kernel: igb 0000:01:00.0 enp1s0: renamed from eth0 Oct 08 09:38:44 sb-0001c0237244 kernel: igb 0000:01:00.0: added PHC on enp1s0 Oct 08 09:38:44 sb-0001c0237244 kernel: igb 0000:01:00.0: Intel(R) Gigabit Ethernet Network Connection Oct 08 09:38:44 sb-0001c0237244 kernel: igb 0000:01:00.0: enp1s0: (PCIe:2.5Gb/s:Width x1) 00:01:c0:23:72:44 Oct 08 09:38:44 sb-0001c0237244 kernel: igb 0000:01:00.0: enp1s0: PBA No: FFFFFF-0FF Oct 08 09:38:44 sb-0001c0237244 kernel: igb 0000:01:00.0: Using MSI-X interrupts. 2 rx queue(s), 2 tx queue(s) Oct 08 09:38:44 sb-0001c0237244 kernel: igb 0000:02:00.0 eno1: renamed from eth0 Oct 08 09:38:44 sb-0001c0237244 kernel: igb 0000:02:00.0: added PHC on eno1 Oct 08 09:38:44 sb-0001c0237244 kernel: igb 0000:02:00.0: Intel(R) Gigabit Ethernet Network Connection Oct 08 09:38:44 sb-0001c0237244 kernel: igb 0000:02:00.0: eno1: (PCIe:2.5Gb/s:Width x1) 00:01:c0:23:72:51 Oct 08 09:38:44 sb-0001c0237244 kernel: igb 0000:02:00.0: eno1: PBA No: FFFFFF-0FF Oct 08 09:38:44 sb-0001c0237244 kernel: igb 0000:02:00.0: Using MSI-X interrupts. 2 rx queue(s), 2 tx queue(s) Oct 08 09:38:47 sb-0001c0237244 kernel: igb 0000:01:00.0 enp1s0: igb: enp1s0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX/TX Oct 08 09:38:48 sb-0001c0237244 kernel: igb 0000:02:00.0 eno1: igb: eno1 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX/TX === The network configuration for "eno1" looks like (10-ethernet-eno1.network) === [Match] Name=eno1 [Network] DHCP=no Address=10.10.69.1/24 Address=10.10.69.200/24 Address=10.10.69.201/24 Address=10.10.69.202/24 === The network configuration for "enp1s0" looks like (10-ethernet-enp1s0.network) === [Match] Name=enp1s0 [Network] DHCP=ipv4 === If the network cable on enp1s0 is unplugged the assigned address is dropped and the interface went down. If the cable is plugged in again, the interface goes up and requests an address using DHCP. If the network cable on eno1 is unplugged the assigned addresses are dropped and the interface went down. If the cable is plugged in again, the interface does NOT go up but stays down. I enabled the debug log level for systemd-networkd. If the cable of eno1 is unplugged I see: === Oct 08 09:45:26 sb-0001c0237244 systemd-networkd[294]: eno1: Flags change: -LOWER_UP -RUNNING Oct 08 09:45:26 sb-0001c0237244 systemd-networkd[294]: Sent message type=signal sender=n/a destination=n/a path=/org/freedesktop/network1/link/_35 interface=org.freedesktop.DBus.Properties member=PropertiesChanged cookie=37 reply_cookie=0 signature=sa{sv}as error-name=n/a error-message=n/a Oct 08 09:45:26 sb-0001c0237244 systemd-networkd[294]: eno1: Lost carrier Oct 08 09:45:26 sb-0001c0237244 systemd-networkd[294]: NDISC: Stopping IPv6 Router Solicitation client Oct 08 09:45:26 sb-0001c0237244 systemd-networkd[294]: eno1: Removing address 10.10.69.202 Oct 08 09:45:26 sb-0001c0237244 systemd-networkd[294]: eno1: Removing address 10.10.69.200 Oct 08 09:45:26 sb-0001c0237244 systemd-networkd[294]: eno1: Removing address 10.10.69.201 Oct 08 09:45:26 sb-0001c0237244 systemd-networkd[294]: eno1: Removing address 10.10.69.1 Oct 08 09:45:26 sb-0001c0237244 systemd-networkd[294]: eno1: State is configured, dropping config Oct 08 09:45:26 sb-0001c0237244 systemd-networkd[294]: eno1: Removing address: 10.10.69.202/24 (valid forever) Oct 08 09:45:26 sb-0001c0237244 systemd-networkd[294]: eno1: Removing address: 10.10.69.200/24 (valid forever) Oct 08 09:45:26 sb-0001c0237244 systemd-networkd[294]: eno1: Removing address: 10.10.69.201/24 (valid forever) Oct 08 09:45:26 sb-0001c0237244 systemd-networkd[294]: eno1: Removing address: 10.10.69.1/24 (valid forever) === If the cable is plugged in again, no additional message appears. Before I updated to Buster I run into this bug: https://github.com/systemd/systemd/issues/5625 This could be worked around using: "IPv6AcceptRA=no" and "LinkLocalAddressing=no" I don't run into this error after updating anymore (it has been about DHCP). Using that lines (regardless if no or yes is choosen) for the static interface on Buster does not make any difference, so the error is different. But while reading that bug, I assume the NDISC message above could be a signal that something went wrong... Upstream accepts bug reports only for the two most recents systemd version (243 and 242), so I cannot report it upstream. Can you help? Best regards, Markus