However, by default, systemd-networkd supplies an 'opaque' client-ID that was generated from the contents of /etc/machine-id.Īccording to the DHCP protocol, leases are chosen by client ID first (as long as the client supplies a 'client ID' option, which may or may not be MAC-based), then by the MAC address only if the client didn't send an ID.

Another common type is '00' (domain name). Mos DHCP clients, including dhclient, supply a client-ID field of type '01' (MAC-based). (It generates the ID based on /etc/machine-id.) If your systemd version is recent enough and if you have direct control over the config files written out by cloud-init, you can tell systemd-networkd to send a MAC-address-based client ID via the *.network file: īut if you know that systemd-networkd will always be used, you can just assign the correct lease to client ID 032e827c00020000ab11d0fc617dced58a43, because that's what systemd-networkd will always send for that machine. There's no way networkd could know why it's being denied, so it won't just magically switch to a different ID type if you do so. What's the right way to avoid this? Deny leases for the long UID? Where does that UID come from in the first place? The NIC is onboard in a Dell PowerEdge R710 server.ĭenying the lease won't work. On the Windows DHCP, the wrong lease (.162) shows a long 'Unique ID' that does not contain any MAC address present on the ubuntu box: 032e827c00020000ab11d0fc617dced58a43 Manually calling dhclient after login (verbose): # dhclient -v eno4 Jul 12 10:10:57 skprov2 systemd-networkd: eno4: DHCP lease lost Jul 12 10:10:56 skprov2 systemd-networkd: eno1: DHCP lease lost Journalctl entries for DHCP: #journalctl | grep -Ei 'dhcp'` My 50-courtin-networking.cfg (cloud-init cfg) network:

The DHCP Server is a Windows box where a reservation was manually configured using the MAC address shown by ip addr in ubuntu (without colons): 5: eno4: mtu 1500 qdisc mq state UP group default qlen 1000 Running dhclient after boot on the interface results in the right IP being added to the interface. I'm experiencing a weird issue where my Ubuntu 18.04 (server) box gets issued a wrong IP address during boot from the DHCP server.

Mac address ubuntu 18.04