Netplan ID's with weird MAC Address in Windows DHCP Server

Bug #1759532 reported by purity on 2018-03-28
This bug affects 4 people
Affects Status Importance Assigned to Milestone

Bug Description

I installed an Ubuntu Server 17.10 to an ESXi 6.5 host with the VMXNET3 adapter.

I'm running our DHCP on a Windows Server 2012.

When the VM connects to the DHCP the DHCP server get a very weird MAC address from the server, like this,


But the MAC address on the VM in vCenter looks all normal.

I have also tried with another adapter, E1000E but still the same weirdness.

netplan config file.


# This file describes the network interfaces available on your system
# For more information, see netplan(5).
  version: 2
  renderer: networkd
      dhcp4: yes
      dhcp6: no

When I disabled netplan through /etc/default/grub with the following line,
GRUB_CMDLINE_LINUX="ipv6.disable=1 netcfg/do_not_use_netplan=true"

and also renamed the /etc/netplan/01-netcfg.yaml to /etc/netplan/01-netcfg.yaml.bak

and configured the old interfaces file,


# /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)
# Generated by debian-installer.

# The loopback interface
auto lo
iface lo inet loopback
auto ens160
iface ens160 inet dhcp

and untagged the following line in /etc/default/networking

it works as it should, the DHCP server get's the right MAC address and I can use my reservation.

Ryan Harper (raharper) wrote :

I believe you are seeing a DHCP Client Identifier instead MAC address; netplan's
networkd backend defaults to using this as the client ID instead of MAC.

I think you want to switch to using MAC as the DHCP client id:


purity (purity82) wrote :

Where should I put that configuration line? It was not so clear in the askubuntu question.

Can't I have some configuration line in the .yaml file for netplan to use MAC instead of that Client Identifier?


Ryan Harper (raharper) wrote :

You shouldn't have to know where to put the networkd config which is exactly the point of the original bug; when bug #1738998 is resolved, it will include information on what configuration to put in the netplan yaml to enable MAC as DHCP Client Identifier.

In the meantime you can:

1) cp /run/systemd/network/ /etc/systemd/network/
2) update /etc/systemd/network/ to add in ClientIdentifier=mac under the [DHCP] section
3) systemctl restart systemd-networkd

purity (purity82) wrote :

Thanks, that worked fine. =)

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