Multiple IP addresses on Ubuntu Core 18

device
1

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.

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cat /etc/netplan/00-snapd-config.yaml 
# This is the network config written by 'console_conf'
network:
  ethernets:
     eth0:
      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?

2

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.

3

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)

4

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).

5

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.

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6

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

7

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

8

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?

9

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