mrankitvish / proxmox-bridge-nat

Creating virtual network for guests on Proxmox, And NAT to get Internet access.

Virtual Network Setup Guide for Proxmox

This guide will walk you through the process of setting up a Linux bridge and configuring network settings using Proxmox WebUI.

Step 1: Create a Linux Bridge and Assign IP using Proxmox WebUI

Create a Linux bridge with the name vmbr1 and assign it the IP address 10.0.0.1/24.

Step 2: Edit /etc/network/interfaces

Edit the /etc/network/interfaces file and add the following lines under your virtual bridge vmbr1. Make sure to adjust the values according to your specific configuration:

post-up   echo 1 > /proc/sys/net/ipv4/ip_forward
post-up   iptables -t nat -A POSTROUTING -s '10.0.0.0/24' -o vmbr0 -j MASQUERADE
post-down iptables -t nat -D POSTROUTING -s '10.0.0.0/24' -o vmbr0 -j MASQUERADE
post-up   iptables -t raw -I PREROUTING -i fwbr+ -j CT --zone 1
post-down iptables -t raw -D PREROUTING -i fwbr+ -j CT --zone 1

The entire interface configuration should look like this:

auto lo
iface lo inet loopback

iface enp30s0 inet manual

auto vmbr0
iface vmbr0 inet static
        address 192.168.29.5/24
        gateway 192.168.29.1
        bridge-ports enp30s0
        bridge-stp off
        bridge-fd 0
auto vmbr1
iface vmbr1 inet static
        address 10.0.0.1/24
        bridge-ports none
        bridge-stp off
        bridge-fd 0
        post-up   echo 1 > /proc/sys/net/ipv4/ip_forward
        post-up   iptables -t nat -A POSTROUTING -s '10.0.0.0/24' -o vmbr0 -j MASQUERADE
        post-down iptables -t nat -D POSTROUTING -s '10.0.0.0/24' -o vmbr0 -j MASQUERADE
        post-up   iptables -t raw -I PREROUTING -i fwbr+ -j CT --zone 1
        post-down iptables -t raw -D PREROUTING -i fwbr+ -j CT --zone 1

Step 3: Enable IP Forwarding

Edit the file /etc/sysctl.conf and add or uncomment the following line to enable IP forwarding:

net.ipv4.ip_forward=1

Then, run the following command to apply the changes:

sysctl -p

Step 4: Save the IPTables Configuration Save the IPTables configuration by running the following commands:

iptables -t nat -A POSTROUTING -o vmbr0 -j MASQUERADE
iptables-save | tee /etc/iptables/rules.v4

Step 5: Reboot

Reboot your system to apply the changes. That's it! Your Linux bridge setup is now complete.