1. How to Delete Default Gateway on Ubuntu 20.04

Published 30 July 2026

A default gateway is an IP address usually assigned automatically to a computer on a network that allows it to connect to other networks. It is the address of the router or other device that connects the computer to the wider network. In Ubuntu 20, multiple default gateways can be assigned to a computer, providing redundancy in case one gateway becomes unavailable. However, in some situations, it may be necessary to delete one of the default gateways.

Before deleting a default gateway, check if the remaining gateways are functioning correctly. To view the list of default gateways assigned to a computer, open the terminal and type the command "ip route". The output will display a list of all routes, including the default gateways. If any of the gateways are marked as "down" or "unreachable," they should be deleted. To delete a default gateway, use the command "ip route del default via " where is the IP address of the gateway you want to delete. For example, to delete the default gateway with the IP address 192.168.1.1, you would type the command "ip route del default via 192.168.1.1".

After deleting a default gateway, verify that the computer can still connect to the network. If the computer is unable to connect, it may be necessary to add a new default gateway. To add a new default gateway, use the command "ip route add default via " where is the IP address of the new gateway. For example, to add a new default gateway with the IP address 192.168.1.2, you would type the command "ip route add default via 192.168.1.2".

Understanding Default Gateways

A default gateway is a network device that connects a local area network (LAN) to other networks. It acts as the primary route for network traffic between the LAN and the rest of the Internet. Multiple default gateways can be configured on a system, but only one can be active at a time.

By default, Ubuntu assigns a default gateway to each network interface. However, you may encounter situations where you need to modify the default gateway configuration, such as when adding a new network route or removing an existing one.

Route Table

The kernel maintains a routing table that stores the list of default gateways and their associated network routes. You can view the routing table using the following command:

The output of this command will display a table similar to this:

In this table, the first entry represents the default gateway for the system. It shows that the gateway IP address is 192.168.1.1 and the interface is eth0.

Identifying Default Gateways

1. Open a terminal window

2. Run the following command:

This command will display the routing table for your system. The default gateway will be listed as the gateway for the 0.0.0.0/0 network.

For example, if your default gateway is 192.168.1.1, the output of the command will look like this:

```
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.1.1 0.0.0.0 UG 100 0 0 eth0
```

3. Find the default gateway

In the example above, the default gateway is 192.168.1.1.

Removing Gateways with the Delete Option

If you have added multiple default gateways to your Ubuntu 20 system, you may want to delete one of them. You can do this using the ip command with the delete option. The syntax for this command is as follows:

Where:

For example, to delete the default gateway 192.168.1.1 on the interface enp0s3, you would run the following command:

You can also use the nmcli command to delete a default gateway. The syntax for this command is as follows:

Where:

For example, to delete the default gateway for the network connection Wired connection 1, you would run the following command:

Once you have deleted the default gateway, your system will no longer use it to route traffic. You can verify that the gateway has been deleted by running the ip route command.

Modifying the Gateway Table

To modify the default gateway table, you'll need to use the 'route' command. This command allows you to view and manipulate the kernel's routing table, which contains a list of all the known routes to different networks and their corresponding gateways.

Here's an example of how to use the 'route' command to view the current default gateway:

$ route -n

Kernel IP routing table

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface

0.0.0.0         192.168.1.1     0.0.0.0         UG    0      0        0 eno1

192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 eno1

As you can see, the default gateway for this system is 192.168.1.1. To delete this gateway, you would use the following command:

$ sudo route del default gw 192.168.1.1

This command will remove the default gateway from the routing table. You can verify that the gateway has been deleted by running the 'route -n' command again.

Once you have deleted the default gateway, you will need to add a new one. To do this, you can use the 'route add' command. For example, to add a new default gateway of 192.168.2.1, you would use the following command:

$ sudo route add default gw 192.168.2.1

You can verify that the new gateway has been added by running the 'route -n' command again.

Permanent Gateway Removal

Step 1: Identify the Default Gateway

Before removing a default gateway, you need to identify it using the 'route -n' command:

Step 2: Open the Network Interfaces File

Use a text editor to open the network interfaces file:

Step 3: Locate the Gateway Configuration

Locate the section for the network interface that uses the default gateway you want to remove. It usually starts with "auto eth0" or "iface eth0 inet static".

Step 4: Remove the Gateway Line

Within the interface section, find the line that contains "gateway" and delete it.

Step 5: Save and Exit the File

Save the changes to the file and exit the editor.

Step 6: Restart Networking

Finally, restart the networking service using one of the following methods:

How to Delete One Default Gateway on Ubuntu 20

Prerequisites

Ensure you have superuser privileges (root) or have access to a user account configured with 'sudo' privileges.

Have a network interface configured with multiple default gateways.

Procedure

1. Identify the Default Gateway to be Removed

   Execute the command:
   

   route -n

   to display the network routing table.
2. Delete the Default Gateway

   Use the command:
   

   route del default gw [Default Gateway Address]

   where '[Default Gateway Address]' is the IP address of the gateway to delete.
3. Verify the Gateway Removal

   Run the command:
   

   route -n

   again to verify that the default gateway entry has been removed.

Common Gateway Removal Errors

Error: Destination Address Required

Possible Causes:

• The 'route del' command was executed without specifying a destination address (default gateway address).

Solution:

• Ensure to provide the IP address of the default gateway to delete in the 'route del' command.

Error: Network is Unreachable

Possible Causes:

• After removing the default gateway, no other valid default gateway is available for the network interface.

Solution:

• Configure an alternative default gateway for the network interface to ensure continued network connectivity.

Error: Sudo Privileges Required

Possible Causes:

• The command was executed without elevated privileges.

Solution:

• Execute the command with 'sudo' or switch to a user account with root privileges.

Troubleshooting Gateway Removal Issues

1. Verify Gateway Removal

Run the 'route -n' command to confirm the gateway has been removed. If it is still listed, repeat the deletion process.

2. Network Interface Status

Check the status of the network interface using 'ifconfig'. Ensure it has an IP address and is configured properly.

3. Default Route Table

Use 'ip route' to check the default route table. If a default gateway is still present, remove it using 'ip route del default via [gateway IP]'.

4. Gateway is Dynamic

If the gateway is assigned dynamically through DHCP, it may automatically re-add itself after removal. Disable DHCP or manually configure a static IP address.

5. Network Manager

Check the NetworkManager configuration. It may be overriding the gateway deletion. Disable or modify its settings accordingly.

6. Systemd Network Configuration

In systemd-based systems, network configuration may be managed through systemd services. Check for any gateway definitions in '/etc/systemd/network' and modify them if necessary.

7. Persistent Network Scripts

In Ubuntu 20, persistent network scripts may still be used. Check '/etc/network/interfaces' for any gateway configurations and remove them manually.

8. In-Depth Troubleshooting

For more detailed troubleshooting, consider the following steps:

Best Practices for Gateway Management

To ensure the reliability and efficiency of network connectivity, it is essential to adhere to best practices for gateway management:

• Determine Critical Gateways: Identify and prioritize gateways that are crucial for business operations and should be closely monitored.
• Monitor Gateway Health: Regularly monitor gateway performance metrics like uptime, latency, and bandwidth utilization to detect potential issues early on.

• Redundancy and Load Balancing: Implement gateway redundancy and load balancing to minimize the impact of single gateway failures and distribute traffic efficiently.
• Firmware Updates: Regularly apply firmware updates to keep gateways secure and address any performance issues or vulnerabilities.

9. Gateway Removal and Reconfiguration

To remove an unnecessary or redundant gateway:

• Identify Gateway to Remove: Determine which gateway should be removed based on network requirements and redundancy levels.
• Update Routing Tables: Modify routing tables to remove the gateway's IP address as a default gateway.
• Reconfigure Gateway: Disable the gateway and set it to a non-default status to prevent conflicts.
• Verify Operation: Test network connectivity to ensure no disruption occurred due to gateway removal.

Additional Considerations

1. Multiple Gateways

sudo nano /etc/network/interfaces

auto eth0

iface eth0 inet dhcp

sudo systemctl restart networking

ip route | grep default

default via 192.168.1.1 dev eth0

sudo nano /etc/network/interfaces

auto eth0

iface eth0 inet dhcp

gateway 192.168.1.1

sudo systemctl restart networking