Debian containers and DHCP


Active Member
Aug 17, 2017
I admin a four node cluster that has recently been upgraded from Debian Stretch, and Proxmox 5.x, to Debian Buster and Proxmox 6.x. The latest updates are installed on all nodes. After upgrading the cluster I moved my focus to the LXC containers and QEMU virtual machines. The VMs had no issues as did most of the containers. However some of the Debian containers showed an interesting issue with DHCP.

All of these containers were set to pull a reserved DHCP address from our Windows AD servers. Before the upgrade there was no issue with this however after upgrading from Debian 8/9 to 10 the DHCP reservation stopped working. The MAC address had not changed in the contain nor had it changed in the DHCP reservation but the containers were pulling an IP address from the general DHCP pool.

As this only happened with the LXC containers and none of the VMs that also use DHCP I thought to ask here first if anyone had a similar issue or if anyone could help to point me in the right direction.
What happens if you run dhclient -v inside the container? Which MAC address do you see? Which one do you see from the DHCP server side?


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