After Installing Proxmox the Node Loses Internet

[wiredbrother]

Hello, everyone!

I have been attempting to install Proxmox on a Debian Stretch and have finally succeeded in getting to the GUI.
I have followed this guide to accomplish this:
pve.proxmox(dot)com/Install_Proxmox_VE_on_Debian_Stretch

Everything was working as expected for the installation until we got to the Network Bridge Setup. At this point, the GUI, Internet, and Node are all working well and going strong. I set up the Linux Bridge on the GUI following several sources on the internet. Here is my main source: pve.proxmox(dot)com/wiki/Network_Configuration

After creating the Linux Bridge (and a reboot to apply changes) the node's internet is no longer working. Before rebooting I was able to snag this log from networking.
Also attached was my interfaces file after Linux Bridge but before Reboot.
Now looking at that log below I know that the physical device is not eth0 it's usually: enp5s0f0 and/or enp5s0f1

Any help would be much appreciated and of course, I can try and answer any questions you all might have.

Thank you,
- wiredbrother

-- Unit networking.service has begun starting up.
Dec 22 00:55:25 bertha dhclient[7957]: Internet Systems Consortium DHCP Client 4.3.5
Dec 22 00:55:25 bertha dhclient[7957]: Copyright 2004-2016 Internet Systems Consortium.
Dec 22 00:55:25 bertha ifup[7923]: Internet Systems Consortium DHCP Client 4.3.5
Dec 22 00:55:25 bertha ifup[7923]: Copyright 2004-2016 Internet Systems Consortium.
Dec 22 00:55:25 bertha ifup[7923]: All rights reserved.
Dec 22 00:55:25 bertha ifup[7923]: For info, please visit isc(dot)org/software/dhcp/
Dec 22 00:55:25 bertha dhclient[7957]: All rights reserved.
Dec 22 00:55:25 bertha dhclient[7957]: For info, please visit isc(dot)org/software/dhcp/
Dec 22 00:55:25 bertha dhclient[7957]:
Dec 22 00:55:25 bertha ifup[7923]: Cannot find device "eth0"
Dec 22 00:55:25 bertha dhclient[7957]: Failed to get interface index: No such device
Dec 22 00:55:25 bertha dhclient[7957]:
Dec 22 00:55:25 bertha ifup[7923]: Failed to get interface index: No such device
Dec 22 00:55:25 bertha ifup[7923]: If you think you have received this message due to a bug rather
Dec 22 00:55:25 bertha ifup[7923]: than a configuration issue please read the section on submitting
Dec 22 00:55:25 bertha ifup[7923]: bugs on either our web page at isc(dot)org or in the README file
Dec 22 00:55:25 bertha ifup[7923]: before submitting a bug. These pages explain the proper
Dec 22 00:55:25 bertha ifup[7923]: process and the information we find helpful for debugging..
Dec 22 00:55:25 bertha ifup[7923]: exiting.
Dec 22 00:55:25 bertha dhclient[7957]: If you think you have received this message due to a bug rather
Dec 22 00:55:25 bertha dhclient[7957]: than a configuration issue please read the section on submitting
Dec 22 00:55:25 bertha dhclient[7957]: bugs on either our web page at isc(dot)org or in the README file
Dec 22 00:55:25 bertha dhclient[7957]: before submitting a bug. These pages explain the proper
Dec 22 00:55:25 bertha dhclient[7957]: process and the information we find helpful for debugging..
Dec 22 00:55:25 bertha dhclient[7957]:
Dec 22 00:55:25 bertha dhclient[7957]: exiting.
Dec 22 00:55:25 bertha ifup[7923]: ifup: failed to bring up eth0
Dec 22 00:55:25 bertha systemd[1]: networking.service: Main process exited, code=exited, status=1/FAILURE
Dec 22 00:55:25 bertha systemd[1]: Failed to start Raise network interfaces.
-- Subject: Unit networking.service has failed
-- Defined-By: systemd
-- Support: (debian website)
--
-- Unit networking.service has failed.
--
-- The result is failed.
Dec 22 00:55:25 bertha systemd[1]: networking.service: Unit entered failed state.
Dec 22 00:55:25 bertha systemd[1]: networking.service: Failed with result 'exit-code'.

 

[Richard]

Assuming your host is behind a NAT and the gateway is 192.168.1.1 /etc/network/interfaces looks correct. Maybe there is something in /etc/network/interfaces.d directory (from previously installed Debian). If so, delete this/these file(s) and create all network configuration you need via Proxmox GUI.