NAT with DHCP best practice

[totalimpact]

I have seen numerous questions regarding this, vague to little answers. What is the advised method for running multiple VMs behind a NAT on PVE (+dhcp)?

I know of multiple ways to achieve it, but wonder if there is some "best practice" that applies to proxmox?

Method 1:
eth0 no ip
vmbr0 > eth0
vmbr9 > dummy0 > iptables nat to vmbr0

KVMs on vmbr9

attach dhcpd running on pve host to vmbr9

Method 2:
vmbr0 > eth0
vmbr1 > dummy0

assign 2x virtual nics from each br to a VM running pfsense (or other) to reconnect VMs on vmbr1 to vmbr0, running NAT, DHCP, DNS

It appears these guys have gone with some form of method 1:
https://modulesfactory.com/knowledgebase/3/Setting-up-Auto-IP-for-KVM.html

Other thing - it is unclear what the "NAT" check box does in the guest network options.

 

[Mr.Holmes]

Hello totalimpact

For sure I prefer "method 1":

Method 1:
eth0 no ip
vmbr0 > eth0
vmbr9 > dummy0 > iptables nat to vmbr0

KVMs on vmbr9

attach dhcpd running on pve host to vmbr9

This is quite clear structure and easy to handle. If firewall needed use the Proxmox firewall settings!

Other thing - it is unclear what the "NAT" check box does in the guest network options.

The kvm built-in NAT. Not recommended to use it since you cannot adjust anything.

Kind regards

Mr.Holmes