Restart Network Service on AlmaLinux 9 and RHEL 9 – Easy Guide Steps

This tutorial provides a comprehensive guide on how to Restart Network Service on AlmaLinux 9 and RHEL 9. Making modifications to your Internet Protocol (IP) configuration necessitates restarting the network service to ensure that the changes are effectively applied. This article provides an Restart Network Service on AlmaLinux 9 and RHEL 9 guide

You can easily restart the network service using various Linux commands. To that end, the following steps detail some of the commands used to Restart Network Service on AlmaLinux 9 and RHEL 9.

To successfully follow this guide, you need to have access to your server either as a root user or a non-root user with sudo privileges. You can consult the Initial Server Setup guide on AlmaLinux 9 for assistance with this.

Warning: Avoid disabling network services on remotely connected systems, as this will result in losing the connection.

Step 1 – General ifconfig Command – Bring Network Interface up and down

A common method involves using the ifconfig command for managing network interfaces. The ifconfig command can be used to bring a network interface up or down.

First, list your network interfaces on AlmaLinux 9 and RHEL 9 using the following command:

sudo ifconfig -a

This command will display all available network interfaces, including those that are currently down.

To disable a network interface, use the command:

sudo ifdown <network-interface-name>

Replace <network-interface-name> with the actual name of the interface you want to disable (e.g., eth0, enp0s3).

To enable a network interface, use the command:

sudo ifup <network-interface-name>

Again, replace <network-interface-name> with the actual name of the interface you want to enable.

Step 2 – Restart Network Service with NetworkManager on RHEL 9

The NetworkManager service provides a convenient way to restart network services in RHEL 9 and AlmaLinux 9. Use the following systemctl command to restart your network services:

sudo systemctl restart NetworkManager.service

This command restarts the NetworkManager service, which will then re-initialize all network interfaces. This is a more graceful and reliable way to restart networking compared to directly manipulating individual interfaces.

Step 3 – Restart Network Services with nmcli Tool on RHEL 9

nmcli is another tool for managing NetworkManager on AlmaLinux 9 and RHEL 9.

To disable and then re-enable network services using the nmcli tool, use the following commands:

sudo nmcli networking off
sudo nmcli networking on

The nmcli networking off command disables all network connections managed by NetworkManager, effectively disconnecting the system from the network. The nmcli networking on command then re-enables network connections, allowing the system to reconnect using the configured profiles.

Conclusion

This article has shown you how to use various Linux commands to disable or enable network interfaces and Restart Network Service on AlmaLinux 9 and RHEL 9. You now have multiple tools in your arsenal to manage your network configurations.

Hope you found this helpful. Please leave a comment if you have any questions or suggestions.

You might also be interested in these articles:

• How To Configure Networking on AlmaLinux
• Test Network Throughput with Iperf Tool on Linux
• Monitor Linux Network Bandwidth Usage with nload Command

Alternative Solutions for Restarting Network Services

While the previous methods are effective, here are two alternative approaches to restarting network services on AlmaLinux 9 and RHEL 9, providing even more flexibility and control.

Alternative 1: Using the ip command

The ip command is a powerful and modern tool for managing network interfaces in Linux. It provides more features and flexibility compared to the older ifconfig command. Instead of bringing interfaces down and up individually, you can use the ip command to flush the IP addresses associated with an interface, effectively forcing a refresh of the network configuration.

Explanation:

This method focuses on refreshing the IP address configuration of a specific network interface. By flushing the existing addresses and allowing the system to reacquire them (either through DHCP or static configuration), you can often resolve network issues without a full service restart. This is less disruptive than restarting NetworkManager.

Code Example:

First, identify the interface you want to refresh:

ip addr show

This command lists all network interfaces and their associated IP addresses. Identify the interface you wish to refresh (e.g., enp0s3).

Next, flush the IP addresses associated with that interface:

sudo ip addr flush dev enp0s3

Replace enp0s3 with the actual name of your network interface. This command removes all IP addresses from the specified interface.

Finally, bring the interface back up:

sudo ip link set dev enp0s3 up

This command activates the interface. The system will then attempt to reacquire an IP address, either through DHCP or by applying the static configuration defined in your network configuration files.

Case Study:

Imagine a scenario where a server’s DHCP lease has expired, and the server is no longer able to connect to the network. Instead of restarting the entire NetworkManager service, you can use the ip command to flush the IP address of the affected interface and then bring it back up. This will force the server to request a new DHCP lease, potentially resolving the connectivity issue without disrupting other network services. For instance, if the interface eth0 is having issues, the commands would be:

sudo ip addr flush dev eth0
sudo ip link set dev eth0 up

Alternative 2: Using nmcli connection down/up

This method leverages NetworkManager’s connection profiles to manage network interfaces. Instead of directly manipulating the interfaces, you can disable and re-enable specific connection profiles, allowing NetworkManager to handle the underlying interface management. This is especially useful in environments with complex network configurations managed by NetworkManager.

Explanation:

NetworkManager uses connection profiles to store network settings for different networks. By deactivating and reactivating a specific profile, you can effectively restart the network connection associated with that profile, triggering a reconnection and reconfiguration. This method is more targeted than restarting the entire NetworkManager service, and it allows you to isolate the changes to a specific network connection.

Code Example:

First, identify the connection profile associated with the interface you want to restart:

nmcli connection show

This command lists all available connection profiles. Identify the profile associated with the network interface you want to restart (e.g., "Wired connection 1").

Next, disable the connection profile:

sudo nmcli connection down "Wired connection 1"

Replace "Wired connection 1" with the actual name of your connection profile.

Finally, enable the connection profile:

sudo nmcli connection up "Wired connection 1"

Again, replace "Wired connection 1" with the actual name of your connection profile.

Case Study:

Consider a server with multiple network interfaces, each configured with a different connection profile. If one of the interfaces is experiencing connectivity issues, you can use the nmcli connection down/up commands to restart the specific connection profile associated with that interface. This will allow you to resolve the issue without disrupting the other network connections. For example, if the profile name is MyEthernet, the commands would be:

sudo nmcli connection down "MyEthernet"
sudo nmcli connection up "MyEthernet"

By providing these alternative methods, you gain a more granular understanding of network management on AlmaLinux 9 and RHEL 9, enabling you to choose the most appropriate solution for your specific needs.