Note: I set-up a Noble container running the latest Netplan version and copy&pasted your configuration from above. It seems to apply without any issue.
# apt list netplan.io Listing... Done netplan.io/noble-updates,noble-security,now 1.0-2ubuntu1.2 amd64 [installed,automatic] # cat /etc/netplan/test.yaml network: version: 2 renderer: networkd ethernets: enp4s0: dhcp4: false enp6s0: dhcp4: false enp9s0: dhcp4: false addresses: - "172.30.30.1/24" nameservers: addresses: - 10.21.21.21 enp3s0f0: dhcp4: false enp3s0f1: dhcp4: false # netplan generate ** (generate:741): WARNING **: 13:21:49.673: Permissions for /etc/netplan/test.yaml are too open. Netplan configuration should NOT be accessible by others. # cat /run/systemd/network/10-netplan-enp* [Match] Name=enp3s0f0 [Network] LinkLocalAddressing=ipv6 [Match] Name=enp3s0f1 [Network] LinkLocalAddressing=ipv6 [Match] Name=enp4s0 [Network] LinkLocalAddressing=ipv6 [Match] Name=enp6s0 [Network] LinkLocalAddressing=ipv6 [Match] Name=enp9s0 [Network] LinkLocalAddressing=ipv6 Address=172.30.30.1/24 DNS=10.21.21.21 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2074266 Title: 24.04: latest netplan updates fail to apply already working config To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/netplan.io/+bug/2074266/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs