Linux Networking: Add multiple gateways (redundancy) on Ubuntu with netplan (Backup Gateway in the Same Network)

Purpose of this configuration

Configuring multiple gateways on Ubuntu using Netplan provides essential network redundancy and failover capabilities, crucial for maintaining connectivity in diverse networking environments. This guide explores how to set up and manage primary and backup gateways within the same network using Netplan, ensuring reliable network access and seamless failover when encountering connectivity issues.

More about netplan you can find at the link.

Steps to be Done to Add Backup Gateway

Configuration file is located under the folder: /etc/netplan

# List files in the folder
ls /etc/netplan

# Edit the file
sudo nano 00-installer-config.yaml

Content of the file:

network:
    renderer: networkd
    version: 2
    ethernets:
        eth0:
            dhcp4: false
            addresses: [192.168.19.189/24]
            gateway4: 192.168.19.252
            optional: true
            nameservers:
                addresses: [192.168.19.11, 8.8.8.8]
            #routes:
             - to: 0.0.0.0/0
               via: 192.168.19.252  # Primary gateway IP
               metric: 100  # Lower metric means higher priority
               on-link: yes
             - to: 0.0.0.0/0
               via: 192.168.19.1  # Backup gateway IP
               metric: 1000  # Higher metric means lower priority
               on-link: yes

This configuration directs all traffic (0.0.0.0/0) through the primary gateway 192.168.19.252 with a lower metric (higher priority).

Test and Apply configuration:

# Try the configuration before applying
netplan try -timeout 120 

# Apply network configuration
netplan apply

Other topics related to the netplan:

• Linux Networking: Add VLAN on Ubuntu with netplan
• Linux Networking: netplan DHCP Configuration on Ubuntu
• Linux Networking: netplan Network Configuration on Ubuntu
  

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