Public bug reported: This is identical to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1881207
It just happens to affect 22.04.1. I can confirm that removing the `interface-mtu XXXX` option from my dhcp server cures the issue. My netplan looks like: network: ethernets: enp33s0f0: dhcp4: true dhcp6: false enp33s0f1: dhcp4: true dhcp6: false This snippet is from my test when I changed the dhcpd to no longer serve MTU: #### Dec 10 00:47:42 wiyuda-echo systemd[1]: Startup finished in 6min 14.070s (firmware) + 2.667s (loader) + 25.861s (kernel) + 3min 53.796s (userspace) = 10min 36.395s. Dec 10 00:47:42 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:47:42 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Lost carrier Dec 10 00:47:42 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCP lease lost Dec 10 00:47:42 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv6 lease lost Dec 10 00:47:43 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:47:46 wiyuda-echo kernel: igb 0000:21:00.0 enp33s0f0: igb: enp33s0f0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX Dec 10 00:47:46 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Gained carrier Dec 10 00:47:46 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:47:51 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv4 address 172.16.214.138/16 via 172.16.0.3 Dec 10 00:47:51 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:47:51 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Lost carrier Dec 10 00:47:51 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCP lease lost Dec 10 00:47:51 wiyuda-echo kernel: igb 0000:21:00.0 enp33s0f0: Reset adapter Dec 10 00:47:52 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv6 lease lost Dec 10 00:47:52 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:47:52 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:47:55 wiyuda-echo kernel: igb 0000:21:00.0 enp33s0f0: igb: enp33s0f0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX Dec 10 00:47:55 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Gained carrier Dec 10 00:47:55 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:47:59 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv4 address 172.16.214.138/16 via 172.16.0.3 Dec 10 00:47:59 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:47:59 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Lost carrier Dec 10 00:47:59 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCP lease lost Dec 10 00:47:59 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv6 lease lost Dec 10 00:47:59 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:47:59 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:48:02 wiyuda-echo systemd[1]: systemd-timedated.service: Deactivated successfully. Dec 10 00:48:02 wiyuda-echo kernel: igb 0000:21:00.0 enp33s0f0: igb: enp33s0f0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX Dec 10 00:48:02 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Gained carrier Dec 10 00:48:02 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:48:07 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv4 address 172.16.214.138/16 via 172.16.0.3 Dec 10 00:48:08 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:48:08 wiyuda-echo kernel: igb 0000:21:00.0 enp33s0f0: Reset adapter Dec 10 00:48:08 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Lost carrier Dec 10 00:48:08 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCP lease lost Dec 10 00:48:08 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv6 lease lost #### <- This is when I changed the configuration and restarted the dhcpd. #### Dec 10 00:48:08 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:48:08 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:48:11 wiyuda-echo kernel: igb 0000:21:00.0 enp33s0f0: igb: enp33s0f0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX Dec 10 00:48:11 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Gained carrier Dec 10 00:48:11 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:48:16 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv4 address 172.16.214.138/16 via 172.16.0.3 Dec 10 00:48:16 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:48:15 wiyuda-echo systemd-resolved[4868]: Clock change detected. Flushing caches. Dec 10 00:48:15 wiyuda-echo systemd-timesyncd[4418]: Initial synchronization to time server 172.16.0.3:123 (172.16.0.3). #### There is an upstream fix, the systemd team did update their stuff here: https://github.com/yuwata/systemd/commit/3be1539a9de6db3637b03b7b68686a314e4baa1f with issue: https://github.com/systemd/systemd/issues/18738 ** Affects: systemd (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1999285 Title: systemd-networkd constantly resets link on i350 when attempting to apply dhcp server provided MTU Status in systemd package in Ubuntu: New Bug description: This is identical to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1881207 It just happens to affect 22.04.1. I can confirm that removing the `interface-mtu XXXX` option from my dhcp server cures the issue. My netplan looks like: network: ethernets: enp33s0f0: dhcp4: true dhcp6: false enp33s0f1: dhcp4: true dhcp6: false This snippet is from my test when I changed the dhcpd to no longer serve MTU: #### Dec 10 00:47:42 wiyuda-echo systemd[1]: Startup finished in 6min 14.070s (firmware) + 2.667s (loader) + 25.861s (kernel) + 3min 53.796s (userspace) = 10min 36.395s. Dec 10 00:47:42 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:47:42 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Lost carrier Dec 10 00:47:42 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCP lease lost Dec 10 00:47:42 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv6 lease lost Dec 10 00:47:43 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:47:46 wiyuda-echo kernel: igb 0000:21:00.0 enp33s0f0: igb: enp33s0f0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX Dec 10 00:47:46 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Gained carrier Dec 10 00:47:46 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:47:51 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv4 address 172.16.214.138/16 via 172.16.0.3 Dec 10 00:47:51 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:47:51 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Lost carrier Dec 10 00:47:51 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCP lease lost Dec 10 00:47:51 wiyuda-echo kernel: igb 0000:21:00.0 enp33s0f0: Reset adapter Dec 10 00:47:52 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv6 lease lost Dec 10 00:47:52 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:47:52 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:47:55 wiyuda-echo kernel: igb 0000:21:00.0 enp33s0f0: igb: enp33s0f0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX Dec 10 00:47:55 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Gained carrier Dec 10 00:47:55 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:47:59 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv4 address 172.16.214.138/16 via 172.16.0.3 Dec 10 00:47:59 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:47:59 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Lost carrier Dec 10 00:47:59 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCP lease lost Dec 10 00:47:59 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv6 lease lost Dec 10 00:47:59 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:47:59 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:48:02 wiyuda-echo systemd[1]: systemd-timedated.service: Deactivated successfully. Dec 10 00:48:02 wiyuda-echo kernel: igb 0000:21:00.0 enp33s0f0: igb: enp33s0f0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX Dec 10 00:48:02 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Gained carrier Dec 10 00:48:02 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:48:07 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv4 address 172.16.214.138/16 via 172.16.0.3 Dec 10 00:48:08 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:48:08 wiyuda-echo kernel: igb 0000:21:00.0 enp33s0f0: Reset adapter Dec 10 00:48:08 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Lost carrier Dec 10 00:48:08 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCP lease lost Dec 10 00:48:08 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv6 lease lost #### <- This is when I changed the configuration and restarted the dhcpd. #### Dec 10 00:48:08 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:48:08 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:48:11 wiyuda-echo kernel: igb 0000:21:00.0 enp33s0f0: igb: enp33s0f0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX Dec 10 00:48:11 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Gained carrier Dec 10 00:48:11 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:48:16 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv4 address 172.16.214.138/16 via 172.16.0.3 Dec 10 00:48:16 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection. Dec 10 00:48:15 wiyuda-echo systemd-resolved[4868]: Clock change detected. Flushing caches. Dec 10 00:48:15 wiyuda-echo systemd-timesyncd[4418]: Initial synchronization to time server 172.16.0.3:123 (172.16.0.3). #### There is an upstream fix, the systemd team did update their stuff here: https://github.com/yuwata/systemd/commit/3be1539a9de6db3637b03b7b68686a314e4baa1f with issue: https://github.com/systemd/systemd/issues/18738 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1999285/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp