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Ubuntu is one of the most popular Linux distributions. When working with Ubuntu, you might encounter the “network unreachable” error, which completely cuts off internet access while all physical network indicators appear normal.

This issue commonly stems from incorrect network configuration in modern Ubuntu versions (18.04 and later) that use Netplan for network management.

Estimated reading time: 3 minutes

Tracing the Network Unreachable Issue

The problem is typically identified by running the ping google.com command in the terminal and observing the “network unreachable” error. In Ubuntu 18.04+, Netplan configuration files (.yaml) in /etc/netplan/ have replaced the legacy /etc/network/interfaces file.

Solving Network Unreachable

Follow these steps to resolve the issue:

Identify Network Interface Name

First, find your network interface name with this command:

ip -brief link show

Typical output:

enp3s0 UP aa:bb:cc:dd:ee:ff <BROADCAST,MULTICAST,UP,LOWER_UP>

(Interface names usually start with en [Ethernet] or wl [Wireless])

Configure Netplan

Open the Netplan configuration file using a safe text editor like nano:

sudo nano /etc/netplan/*.yaml

Apply one of these configurations based on your needs:

Option 1: DHCP (Recommended)

network:
  version: 2
  renderer: NetworkManager
  ethernets:
    enp3s0:  # REPLACE WITH YOUR INTERFACE NAME
      dhcp4: true
      nameservers:
        addresses: [8.8.8.8, 8.8.4.4, 1.1.1.1]

Option 2: Static Configuration

network:
  version: 2
  renderer: NetworkManager
  ethernets:
    enp3s0:  # REPLACE WITH YOUR INTERFACE NAME
      addresses:
        - 192.168.1.100/24
      routes:
        - to: default
          via: 192.168.1.1  # ROUTER/GATEWAY ADDRESS
      nameservers:
        addresses: [8.8.8.8, 8.8.4.4, 1.1.1.1]

Critical Notes:
1. YAML indentation is crucial – use SPACES ONLY (tabs are invalid)
2. IP addresses, subnet mask, and gateway must match your local network
3. The renderer: NetworkManager line is essential for desktop editions

Apply Changes

After saving the file, apply the configuration:

sudo netplan apply

If errors occur, debug with:

sudo netplan --debug apply

Test your connection:

 ping 8.8.8.8