Editing /etc/network/interfaces to acquire router WAN IP address

[philled]

For weeks I've been trying to get a virtual pfSense machine running on my Proxmox 5 setup. After instaling pfSense over and over I could never get it to acquire an IP address from the cable modem.

Then this morning, as luck would have it, I stumbled across http://909research.com/proxmox-with-sophos-utm-install/ which made me check my /etc/network/interfaces file. After making these simple changes to bridge_ports pfSense got an IP address first time

Before:
auto vmbr1
iface vmbr1 inet manual
bridge_ports none
bridge_stp off
bridge_fd 0

auto vmbr2
iface vmbr2 inet manual
bridge_ports none
bridge_stp off
bridge_fd 0

After:
auto vmbr1
iface vmbr1 inet manual
bridge_ports enp5s0f0
bridge_stp off
bridge_fd 0

auto vmbr2
iface vmbr2 inet manual
bridge_ports enp5s0f1
bridge_stp off
bridge_fd 0

Couple of questions about this:
1) Why did I have to do this? I had assumed that when I set up vmbr1 and vmbr2 in Proxmox this would happen automatically.
2) Is this in some Proxmox docco somewhere that I missed? If it is then I'd like to read it and understand it better.

I hope this helps someone else with a similar problem in future.

 

[philled]

Couple of questions about this:
1) Why did I have to do this? I had assumed that when I set up vmbr1 and vmbr2 in Proxmox this would happen automatically.

I think I can answer my own question here. I don't think I set the Ports/Slaves field when I originally created the bridges in the web GUI. I think I accidentally left them blank.