How to Temporarily Set a Static IP Address on a Linux System

Here’s how to temporarily set a static IP address on a Linux system using command-line tools. These changes will reset after reboot (for permanent setups, edit your network configuration files).

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Method 1: Using the ip Command (Modern Systems)

Step 1: Check Current Network Interface

ip addr show

Identify your active interface (e.g., eth0, enp0s3, or wlan0 for Wi-Fi).

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Step 2: Assign a Static IP Address

sudo ip addr add <IP-Address>/<Subnet-Mask> dev <interface>

Example:

sudo ip addr add 192.168.1.100/24 dev eth0

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Step 3: Set Default Gateway

sudo ip route add default via <Gateway-IP> dev <interface>

Example:

sudo ip route add default via 192.168.1.1 dev eth0

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Step 4: Configure DNS (Optional)

Temporarily add DNS servers to /etc/resolv.conf (may reset on reboot):

echo "nameserver 8.8.8.8" | sudo tee -a /etc/resolv.conf  # Google DNS
echo "nameserver 8.8.4.4" | sudo tee -a /etc/resolv.conf

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Method 2: Using ifconfig & route (Legacy Systems)

Step 1: Assign IP Address

sudo ifconfig <interface> <IP-Address> netmask <Subnet-Mask>

Example:

sudo ifconfig eth0 192.168.1.100 netmask 255.255.255.0

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Step 2: Set Default Gateway

sudo route add default gw <Gateway-IP> <interface>

Example:

sudo route add default gw 192.168.1.1 eth0

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Method 3: Using nmcli (NetworkManager Systems)

sudo nmcli con mod <Connection-Name> ipv4.addresses <IP-Address>/<Subnet-Mask>
sudo nmcli con mod <Connection-Name> ipv4.gateway <Gateway-IP>
sudo nmcli con mod <Connection-Name> ipv4.dns "8.8.8.8,8.8.4.4"
sudo nmcli con up <Connection-Name>

Example:

sudo nmcli con mod "Wired Connection 1" ipv4.addresses 192.168.1.100/24
sudo nmcli con mod "Wired Connection 1" ipv4.gateway 192.168.1.1
sudo nmcli con up "Wired Connection 1"

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Verify the Configuration

ip addr show <interface>     # Check IP assignment
ip route show               # Verify gateway
ping google.com             # Test internet connectivity

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Revert to DHCP (Dynamic IP)

To undo the static IP and return to DHCP:

sudo dhclient <interface>

Example:

sudo dhclient eth0

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Important Notes

• ⚠️ Temporary Changes: These settings do not survive reboots. For permanent setups, edit /etc/network/interfaces (Debian) or /etc/sysconfig/network-scripts/ifcfg-<interface> (RHEL/CentOS).
• 🔧 Interface Names: Use ip link show to confirm your interface name.
• 🔄 NetworkManager: If your system uses NetworkManager, avoid mixing ip/ifconfig with nmcli to prevent conflicts.

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