How to Configure Hostname, static IP, Gateway and DNS on Linux Production Servers

 Introduction

Configuring network infrastructure on a live Linux production server requires absolute precision. Unlike desktop systems or local development environments, enterprise servers demand fixed and reliable network parameters. Single syntax error or misconfigured gateway can break significant dependencies such as locking out monitoring tools, invalidate active firewall rules and causing severe application downtime. 

In this practical Linux server administration guide, we will leave the generic theories and look at the exact commands needed to permanently build your network settings. we will cover modern network configuration management across all major distributions including netplan for Ubuntu Server  environment and NetworkManager (nmcli) for RHEL, Alma Linux and Rocky Linux. 

By the end of this tutorial, you will know:

• How to set and change the hostname permanently in Linux

• How to configure a static IP on Ubuntu and RHEL based servers

• How to set a default gateway on Linux server

• How to set DNS using the command line on a Linux server

• How to verify network settings after applying these settings

Before configuring hostname, static IP addresses, gateways and DNS servers, it is important to understand the fundamentals of Linux networking. Read our guide on Linux Networking Basics for Beginners to learn key networking concepts used in Linux environments.

Why Proper Network Configurations Matter on Production Servers

Production servers require static and reliable network configurations. Dynamic IP addresses are not suitable for enterprise systems because applications, monitoring tools, firewalls and DNS records rely on static network settings.

Proper network configuration helps administrators:

• Maintain reliable connectivity

• Improve server management

• Prevent network conflicts

• Ensure DNS resolution works correctly

• Support automation and monitoring tools

• Improve infrastructure stability

Common Use Cases in Enterprise Linux Environments

network configuration on Linux is normally required for:

• Web servers

• Database servers

• Kubernetes nodes

• Virtual machines

• Cloud instances

• Backup servers

• Mail servers

• Monitoring systems

• DNS servers

• Proxy servers

Understanding Temporary vs Permanent Network Changes in Linux

Temporary Network settings

Some Linux networking commands apply changes only to the running system. These temporary network settings are stored in memory and are lost after reboot or when network service is restarted. Actual purpose of these settings is to test changes before applying permanently.                                         

Permanent Network Configurations

Permanent network configuration settings are saved in network configuration files or managed by tools such as Netplan and Network Manager. These network configurations permanently remain after the system reboot.                                     

Prerequisites before Configuring Linux Network Settings

Before making any network changes to a production configuration file, you have to secure root level execution access and understand your current network setup.

Elevate Privileges

Mostly production environments restrict direct root login. Use sudo to open root access because most network configuration tasks require root privileges. I have used both the root and a user with sudo privileges just to show how the settings take place with both users.

Switch to the root user:

sudo -i

or

su -

Linux networking skills are essential for system administrators, cloud engineers and DevOps professionals. Learn why Linux remains one of the most valuable technologies in modern IT by reading our guide on Why Learn Linux? Real World Uses, Career Opportunities and Practical Benefits.

Identify Your Active Network Interfaces

Before making changes, check your available network interfaces running by:

ip addr show

Common interface names you will encounter:

Interface Name	Description
eth0	Traditional Ethernet interface naming used on older Linux systems
ens3, ens33	Predictable network interface names commonly found on VMware and KVM virtual machines
enp0s3	PCI based Ethernet interface often seen on physical hardware and VirtualBox virtual machines
eno1	Onboard Network Interface Card (NIC) commonly found on enterprise servers such as Dell PowerEdge systems

Pro tip: Use ip link show to see all interfaces including ones that are down.

Create Existing Network Configuration Backup

Never edit a live network configuration without a recovery copy. Always back up network configuration files before making changes.

1. For Ubuntu Server Netplan backup:

cp /etc/netplan/00-installer-config.yaml  /root/

2. For RHEL / Rocky / AlmaLinux (NetworkManager) backup:

cp /etc/NetworkManager/system-connections/ens160.nmconnection /root/

How to Check Current Network Configuration in Linux

Before changing settings, verify the existing network configuration.

1. Check Current Hostname

Use the following command:

hostnamectl

2. View IP Address Information

Check current IP addresses using this command:

ip addr show

3. Check Default Gateway settings

Check the default route with this command:

ip route

4. Verify Configured DNS Servers

Check DNS configuration:

cat /etc/resolv.conf

How to Configure a Permanent Hostname on Linux Servers

Hostnames are critical in enterprise Linux environments for tracking systems across monitoring platforms, central logs and DNS records. Modern Linux distributions manage this identity using the hostnamectl utility, which updates the hostname permanently with requiring a system reboot.

Set a new hostname:

Run the following command to set your new hostname (replace seeklinux with your actual server name)

hostnamectl set-hostname seeklinux

Verify the change:

To immediately Verify that the system identity updated correctly run:

hostnamectl 

You can also verify with:

hostname

or

Update the hosts file

nano /etc/hosts

Why this matters: Many applications (Java apps, Kubernetes, some databases) resolve the local hostname. If /etc/hosts is not synchronized then you will see slow startup times or DNS lookup errors.

How to Configure Static IP Address on Linux

Static IP configuration is important for Linux production servers. Different Linux distributions use different network management tools.

Configure a Static IP on Ubuntu Server (Netplan)

Ubuntu 18.04 and later Ubuntu releases handle network architecture through Netplan which uses YAML files locate in the /etc/netplan directory. 

Before editing, ensure you have located your exact interface name using the ip addr show commnad we ran earlier. Locate the Netplan Configuration File

ls /etc/netplan/

You will typically see a file such as 00-installer-config.yaml or 01-netcfg.yaml. In my case file name is 50-cloud-init.yaml.

Edit the Netplan Configuration File

Open your primary netplan configuration file using a text editor like nano:

sudo nano /etc/netplan/50-cloud-init.yaml

Replace the existing contents with the following configuration block. Make sure to update the interface name IP subnet, gateway and DNS addresses to match your network topology.

Apply and Test the New Netplan Configuration Settings

Once your edits are saved, validate and apply your changes using the try modifier. This safe-mode command automatically rollback your settings if you accidently lock yourself out of ssh session.

sudo netplan try

If the configuration initializes successfully without locking your session, press enter to commit the changes permanently. Alternatively you can apply them directly:

sudo netplan apply

For debugging issues, use:

sudo netplan --debug apply

Important: YAML is indentation sensitive. Use spaces instead of tabs because a single indentation mistake will prevent netplan from loading the configuration.

Configure Static IP Address on RHEL / CentOS / AlmaLinux / Rocky Linux (NetworkManager)

RHEL based distributions manage persistent interfaces using NetworkManager while you can manually modify connection profile. The industry standard method on production environments is utilizing the nmcli command line tool.

Method A: Set Network Parameters Using nmcli (Recommended for Production)

The nmcli command is the most reliable and scriptable way to manage network connections on RHEL based systems.

Step 1: 

Before executing configuration commands, verify your exact connection interface profile name:

nmcli con show

Step 2: Set static IP, gateway and DNS Using nmcli

Run the following commands in sequence to switch your active interface (replace ens160 with your interface name) from dhcp to static configuration. This nmcli command will set the static IP, gateway and DNS on RHEL server.                                                        

Output:

This is the ouput of above command:

Apply and Activate your Network Changes:

Unlike other configuration utilities, NetworkManager requires you to reload and reactivate the interface before the settings take effect on your running server hardware.

Bring the interface down and back up to commit the changes:

nmcli con down ens160 && nmcli con up ens160

Method B: Edit Direct Connection File

On RHEL 8/9, connection files are stored at /etc/NetworkManager/system- connections/ens160.nmconnection:

sudo nano /etc/NetworkManager/system-connections/ens160.nmconnection                     

Apply the changes:

sudo systemctl restart NetworkManager                                                             

Note: On RHEL 9 and Rocky Linux 9 connection profiles are stored under /etc/NetworkManager/system-connections/ as .nmconnection files. Use nmcli command to manage them and avoid editing these files manually unless necessary.

How to Configure Default Gateway on Linux Servers

The gateway allows Linux servers to communicate with external networks and the internet.

Add a Default Gateway (Temporary for testing)

sudo ip route add default via 192.168.1.1 dev ens160                                                            

This remains till reboot. Use it just for a live testing before committing changes to a configuration file.

Configure Gateway with Netplan on Ubuntu

sudo nano /etc/netplan/50-cloud-init.yaml                                                              

Apply changes:
sudo netplan apply                                                                               

Verify Default Route Configuration

Verify gateway settings:

ip route

or

route -n                                                                                      

Set Gateway Using NMCLI on RHEL 9

To configure the gateway using nmcli, you can modify the connection profile and then reactivate it.

nmcli con mod ens160 ipv4.gateway 192.168.1.1                                                                             

Apply changes:

nmcli con up ens160                                                                                      

How to Configure DNS Servers on Linux

DNS configuration is important for production Linux servers because applications depend on hostname resolution.

Configure DNS Using Netplan on Ubuntu

To configure a dns using Netplan on Ubuntu, edit the Netplan YAML file (usually in /etc/netplan/).

sudo nano /etc/netplan/50-cloud-init.yaml

Apply changes:

sudo netplan apply

Configure DNS with NMCLI on RHEL 9

This is a most common method used on modern RHEL, Rocky Linux, AlmaLinux and CentOS to set dns using nmcli command.

nmcli con mod ens160 ipv4.dns "8.8.8.8 1.1.1.1"

Restart the connection:

nmcli con up ens160

Update resolv.conf manually

Temporary DNS configuration:

nano /etc/resolv.conf

Test DNS Resolution in Linux

Test DNS using dig:

dig google.com

Or

 use nslookup:

nslookup google.com

How to Apply and Verify Network Changes

After configuring Linux network settings always verify connectivity.

Restart Networking Services

1. Restart NetworkManager:

systemctl restart NetworkManager

2. Restart systemd-networkd

systemctl restart systemd-networkd

Complete Verification Checklist

# 1. Check IP address

ip addr show ens33

# 2. Check the default gateway

ip route show

# 3. Check DNS configuration

resolvectl status

cat /etc/resolv.conf

# 4. Test gateway connectivity

ping -c 4 192.168.1.1

# 5. Test internet/DNS resolution

ping -c 4 8.8.8.8

ping -c 4 google.com

# 6. Confirm hostname

hostnamectl

# 7. Check if the correct interface is UP

ip link show ens33

Quick Reference Table

What to Check	Command
IP Address	ip addr show
Default Gateway	ip route show
DNS Servers	resolvectl status
Hostname	hostnamectl
Interface Status	ip link show
DNS Resolution Test	dig google.com

Common Errors and How to Fix Them

1. Error: "Network unreachable" after applying static IP address

Cause: Wrong subnet mask or gateway IP Address

Fix: Double check your network range. If your network is 192.168.1.0/24, your gateway must also be in the 192.168.1.x range.

2. Error: DNS resolution is unsuccessful, ping connects to IP address

Reason: DNS servers are unreachable or improperly configured

Fix: Test DNS manually

dig @8.8.8.8 google.com

# Check if systemd-resolved is running

systemctl status systemd-resolved

3. Error: Netplan apply fails with YAML error

Cause: Incorrect indentation or syntax error

Fix: Verify settings in the YAML file before applying changes

sudo netplan generate

4. Error: nmcli changes not persisting after reboot

Cause: connection.autoconnect is set to no

Fix: sudo nmcli con mod ens33 connection.autoconnect yes

5. Error: hostname reverts back to previous after reboot

Cause: hostname command was used instead of hostnamectl

Fix: Always use sudo hostnamectl set-hostname your-hostname

Best Practices for Production Linux Server Networking

Production Linux servers should follow standard networking best practices.

·  Use Static IPs for Production Systems because Static IP addresses minimize connectivity and infrastructure management issues

·  Document Network Changes

·  Maintain records of IP addresses, Gateways, DNS servers, VLANs and Hostnames

·  Always configure primary and secondary DNS servers

·  Avoid Manual Changes to Auto-Generated Files

·  Always use standard configuration tools

·  Test Connectivity before Reboot the system

·  Verify SSH connectivity before restarting remote production servers

Security Considerations of Linux Production Servers

Linux production server security should include proper network management practices.

·  Restrict Unauthorized Network Changes

·  Limits sudo access to trusted administrators only

·  Monitor Network Configuration Changes

Track configuration changes using:

• Git repositories

• Configuration management tools

• Monitoring systems

• Audit logs

·  Use Proper Hostname Naming Conventions

·  Use standard names as hostname

Example:

·  web-prod-01

·  db-prod-01

·  proxy-prod-01

Linux process and service management based on proper network configuration. Learn more in our guide on Linux Process Management for Beginners - Complete Guide.

Difference between Netplan and NetworkManager

A common question when switching between distros is: which tool should I use?

Feature	Netplan	Network Manager
Default On	Ubuntu 18.04+	RHEL, CentOS, Fedora
Configuration Format	YAML files	INI files or nmcli
Backend	systemd-networkd or NetworkManager	NetworkManager daemon
Best For	Servers (with networkd)	Desktops and servers
Scripting	YAML based	nmcli commands
Apply Changes	netplan apply	nmcli con up

Both are solid choices. On Ubuntu servers, stick with netplan + networkd. On RHEL based systems use nmcli.

Frequently Asked Questions (FAQs)

Q1: How to set a static IP address without rebooting in Linux?

Ans: Use ip addr add 192.168.1.100/24 dev ens33 and ip route add default via 192.168.1.1 for a live change then update your Netplan or nmcli configuration for permanent changes.

Q2: How to change the hostname permanently in Linux?

Ans: Run sudo hostnamectl set-hostname new-hostname and update the /etc/hosts. The change immediately takes effect.

Q3: What is the difference between Netplan and NetworkManager?

Ans: Netplan is the default on Ubuntu servers and uses YAML config files. Network Manager is default on RHEL/CentOS and is managed via nmcli. Ultimately both configure the same kernel networking stack.

Q4: How do I configure DNS on Ubuntu 22.04 server?

Ans: Either set DNS in your Netplan YAML under nameservers addresses or configure /etc/systemd/resolved.conf and restart systemd-resolved.

Q5: How to verify network settings in Linux?

Ans: Use ip addr show for IP, ip route show for gateway, resolvectl status for DNS and hostnamectl for hostname.

📚 Related Articles

• 👉 What Is Linux? Complete Beginner's Guide
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• 👉 Managing Users and Groups in Linux
• 👉 Linux Process Management for Beginners – Complete Guide

Verify Your New Linux Network Settings

After applying your changes either on Ubuntu or RHEL-based systems, you must verify that the server successfully communicate with local network and resolve external internet domains. Run these validation commands to ensure every thing is working:

1. Test Internal Gateway Routing:

Ping your default gateway to verify local connectivity ( replace with your gateway IP):

ping -c 3 192.168.1.1

2. Test External DNS Resolution

Verify that your configured DNS servers are resolving domain names by pinging a public address:

ping -c 3 google.com

3. Check Final Hostname Status:

Ensure the system identity holds across active terminal shells:

hostname --fqdn

 

Troubleshooting Check list

If you lose connectivity or cannot ping external domains after applying these steps, walk through this quick emergency checklist:

Check Link State: Run ip link to ensure your interface is marked as up.

Verify Spacing (Ubuntu): re-open /etc/netplan/00-installer-config.yaml and check for accidental tab characters or misaligned lines.

Connection Profile (RHEL): ensure you ran nmcli connection up on the exact active profile name, not just the physical device name.

Mastering these Linux sysadmin skills gives you full control over your server's network identity and connectivity and prevents the kind of outages that come from relying on DHCP in production.

If you found this guide helpful, keep visiting seeklinux for more Linux tutorials, server administration guides and troubleshooting tips.

Author: Aqeel Anwar

SeekLinux Team
Linux Engineers | DevOps | Security Enthusiasts

SeekLinux Team shares practical Linux tutorials, SSL/TLS certificate guides, commands and DevOps solutions. Our goal is to simplify system administration and help you master real-world server and security tasks.

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