Multiple IP addresses on Ubuntu Core 18

I have multiple Ubuntu Core 18 devices running on my network, some of which have multiple IP addresses assigned to them, whereas others don’t.


cat /etc/netplan/00-snapd-config.yaml 
# This is the network config written by 'console_conf'
      addresses: []
       dhcp4: true
       dhcp6: true
       nameservers: {}
  version: 2

I can delete the IP addresses but after a while they show up again.

Any reason this might happen?

Do these devices have network-manager installed on them? If so, then perhaps @abeato can provide some clarity. I’ve seen this happen with old versions of network-manager and UC16, but I don’t know if the same problem would happen with UC18.

i’ve seen that happen before on boards where the MAC changes with each boot due to issues with the NIC driver setup … (though the old ones should not be cached actually)

They don’t, at first I thought it was because I wrote values to /etc/netplan/00-snapd-config.yaml, but have reverted those since (with console-conf).

I’ve rebooted a device multiple times but the MAC stays the same, although after a reboot it comes up with only one IP. The devices are running on a RPi CM3 with pi-kernel 18-cm3.

do you perhaps have any container tools installed that could set up networking per-container (lxd, docker …) ?

looks like all the additional ones come from a different subnet

Normally there shouldn’t be, I’ll disable all snaps and reboot and monitor it to see if that’s the case.

Do you have access to your router to check which IP is really assigned to your device MAC? Could you also share the content of /etc/netplan/* and the installed snaps?

also, could it be that there are two dhcp servers running in your network (by accident or on purpose) ?