Strange DHCP Behavior

Graylog Central (peer support)
1

I have Graylog deployed as a VM from the OVA template. On the VM NIC options I have an automatically generated hardware address. I use this hardware address to reserve an IP on DHCP for this server. When I boot the server, it grabs another random IP from the pool and the hardware address looks strange on DHCP. It’s about 3x longer than it should be and it doesn’t match to anything on the server under ifconfig.

when I do a dhclient release and renew I will get the proper reserved address, but everytime I reboot server it will grab a different IP because of the strange hardware address. If this is expected behavior I will just statically configure IP.

2

Hello @DrVirus
it is a new behavior of new linux machines, which uses DUID as a DHCP identifier instead of MAC address.

If you want to switch back to MAC address, please change netplat config file, add line dhcp-identifier: mac under line dhcp4:yes. Interface enp0s3 is only example, use your real interface name.

sudo vim /etc/netplan/01-netcfg.yaml

enp0s3:
      dhcp4: yes
      dhcp-identifier: mac

For reference:
https://netplan.io/examples#integration-with-a-windows-dhcp-server

3

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