proxmox 8.1 vm not using dhcp

[cd0101]

I installed Proxmox 8.1
This is the network for PVe box. As you can see i have 3 machines, but that is not relevant




Another post on this forum said run this on pve shell so vms could access the inet. I did and that worked.
echo 1 > /proc/sys/net/ipv4/ip_forward

https://forum.proxmox.com/threads/the-vms-are-not-assigned-ip-address-by-dhcp-server.125911/

My host could access internet before this command was entered, but new vms could not


I installed debian 12 in a vm

The setup was able to download updates and apparently setup dhcp.

WHen i rebooted after installation, it tried to grab the IP address of the host and could not ping google.com


I had to give it a static address in /etc/network/interfaces:





Why do i have to use a static address to get it to work?
I don't recall having to do this in proxmox 7.1, but maybe i forgot something.

 

[cheiss]

Hi,

please provide more information.
First, the output of qm config 100 and cat /etc/network/interfaces would be helpful.

Further, how is your DHCP configured (e.g. address range)? Where does it run (externally on a router? built-in SDN?)

How did you then configure the DHCP client in the VM? I guess you are using Debian (12) in the VM? Did you correctly select DHCP configuration during the installation? If not, please have a look here how to configure a DHCP client on Debian.

Another post on this forum said run this on pve shell so vms could access the inet. I did and that worked.
echo 1 > /proc/sys/net/ipv4/ip_forward

This is generally only needed if you have a routed configuration, which you do not - or at least you seem to try to use bridged mode.

 

[cd0101]

Here you go.

root@pve:~# qm config 100
boot: order=scsi0;ide2;net0
cores: 1
cpu: x86-64-v2
ide2: local:iso/debian-12.4.0-amd64-netinst.iso,media=cdrom,size=628M
memory: 2048
meta: creation-qemu=8.1.2,ctime=1706151416
name: k1
net0: virtio=BC:24:11:57:135,bridge=vmbr0
numa: 0
ostype: l26
scsi0: local-lvm:vm-100-disk-0,discard=on,iothread=1,size=32G
scsihw: virtio-scsi-single
smbios1: uuid=727b36bd-3bfd-44cd-9c3e-ef8db536e5c2
sockets: 1
vga: virtio
vmgenid: c0f0e1d1-2a6a-4156-8710-07f9cf0e3fe1



root@pve:~# cat /etc/network/interfaces
# network interface settings; autogenerated
# Please do NOT modify this file directly, unless you know what
# you're doing.
#
# If you want to manage parts of the network configuration manually,
# please utilize the 'source' or 'source-directory' directives to do
# so.
# PVE will preserve these directives, but will NOT read its network
# configuration from sourced files, so do not attempt to move any of
# the PVE managed interfaces into external files!

auto lo
iface lo inet loopback

auto eno1
iface eno1 inet manual

auto vmbr0
iface vmbr0 inet static
address 10.27.1.2/24
gateway 10.27.1.1
bridge-ports eno1
bridge-stp off
bridge-fd 0
bridge-vlan-aware yes
bridge-vids 2-4094

source /etc/network/interfaces.d/*


The physical box running pve is connected to a dumb switch which is in turn connected to PFsense router. The router tags traffic with vlan 50,

I tried with or without the 50 tag in the vm setup but did not seem to help. Only when i did static address inside vm did i get the connection.