How to set a static IP address on a linux server or desktop

Setting Static IP on Linux Servers (Proxmox/Ubuntu)

Overview

This guide shows how to configure a static IP address on a Linux server that is already using the IP you want to keep.

CRITICAL WARNING FOR PROXMOX: Do NOT restart networking service while VMs are running. Changes require a full server reboot.

Prerequisites

• Root/sudo access to the server
• Current IP address you want to make static
• Gateway address (usually 192.168.1.254)
• DNS servers (recommended: 1.1.1.1 and 8.8.8.8)
• For Proxmox: Schedule maintenance window for server reboot

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For Linux Mint / Ubuntu Desktop (NetworkManager)

RECOMMENDED: Use the GUI method

GUI Method (Easiest)

1. Click the network icon in your system tray (bottom right)
2. Click “Network Settings” or “Edit Connections”
3. Find your active connection (e.g., “Auto ORBI08”)
4. Click the gear icon or “Edit”
5. Go to the “IPv4 Settings” tab
6. Change method from “Automatic (DHCP)” to “Manual”
7. Click “Add” and enter:
   • Address: 192.168.1.100 (your desired IP)
   • Netmask: 255.255.255.0 (or enter 24)
   • Gateway: 192.168.1.254
8. In DNS servers field: 1.1.1.1, 8.8.8.8
9. Click “Save”
10. Disconnect and reconnect to the network

Command Line Method (Alternative)

If you must use command line on NetworkManager systems:

# List connections to find your UUID
nmcli connection show

# Modify connection (use your actual UUID)
nmcli connection modify <UUID> ipv4.method manual ipv4.addresses 192.168.1.100/24 ipv4.gateway 192.168.1.254 ipv4.dns "1.1.1.1 8.8.8.8"

# Apply changes
nmcli connection down <UUID> && nmcli connection up <UUID>

# Verify
ip addr show | grep "inet "

Note: NetworkManager can have duplicate connection names. If you see warnings about duplicate names, use the connection’s UUID instead of the name, or use the GUI method.

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For Proxmox / Ubuntu Server

Steps

1. Check Current Configuration

cat /etc/network/interfaces

Look for your network bridge (usually vmbr0 on Proxmox) or main interface.

2. Verify if Already Static

Look for the line starting with iface:

• iface vmbr0 inet static = Already static (just add DNS if missing)
• iface vmbr0 inet dhcp = Using DHCP (needs conversion to static)

3. Edit Network Configuration

nano /etc/network/interfaces

4. Configure Static IP

Find or create the interface section. Example for vmbr0:

auto vmbr0
iface vmbr0 inet static
        address 192.168.1.XXX/24
        gateway 192.168.1.254
        dns-nameservers 1.1.1.1 8.8.8.8
        dns-search tailcf482c.ts.net
        bridge-ports enp1s0
        bridge-stp off
        bridge-fd 0

Replace:

• 192.168.1.XXX with your desired IP
• enp1s0 with your physical interface name (check with ip link show)
• Remove bridge-* lines if not using a bridge

5. Save and Exit

• Press Ctrl+X
• Press Y to confirm
• Press Enter to save

6. Apply Configuration

For Proxmox servers with running VMs:

reboot

Changes will NOT take effect until server is rebooted. Do NOT use systemctl restart networking as this will disconnect all VM networks and require a reboot anyway to restore VM connectivity.

For standalone Ubuntu servers (no VMs):

systemctl restart networking

7. Verify Configuration

After reboot, test connectivity:

ping -c 3 1.1.1.1

For Proxmox: Also verify VMs are reachable after reboot.

If ping works, your static IP is configured correctly.

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Network Configuration Fields Explained

• address: Your static IP with subnet mask (/24 = 255.255.255.0)
• gateway: Your router’s IP address
• dns-nameservers: DNS servers for name resolution
• dns-search: Domain search suffix (if using Tailscale)
• bridge-ports: Physical interface connected to the bridge (Proxmox only)

Notes

• CRITICAL: On Proxmox, always reboot instead of restarting networking service
• Restarting networking on Proxmox will disconnect all VM network interfaces
• Schedule maintenance window for Proxmox hosts
• Always verify network connectivity after changes
• For Linux Mint/Ubuntu Desktop: GUI method is recommended over command line
• For standalone Ubuntu servers without VMs, network restart is safe