How to Configure a Static IPv6 Address on Ubuntu – Step‑by‑Step Guide

What is IPv6

IPv6 (Internet Protocol version 6) is the current IP standard. It uses a 128‑bit address space, provides built‑in IPsec security, eliminates the need for NAT, and supports both stateful and stateless address autoconfiguration (SLAAC). These features increase address availability, simplify routing, and improve security and performance for modern networks.

Managing IPv6 on Ubuntu

Ubuntu enables IPv6 by default. You can inspect and control IPv6 with command‑line tools such as ifconfig or ip, and by editing the network configuration files: /etc/netplan/01‑netcfg.yaml (Ubuntu 18.04 and newer, Netplan) /etc/network/interfaces (older releases, ifupdown)

GUI network managers can also be used, but the following procedure shows the CLI method for a static IPv6 address.

Configuring a Static IPv6 Address

Verify IPv6 support

Open a terminal and list the interfaces. An IPv6 address indicates that the stack is active. ifconfig or

ip a

Edit the network configuration file

For Netplan (Ubuntu 18.04 +), edit the YAML file that exists in /etc/netplan/ . For older systems, edit /etc/network/interfaces . sudo nano /etc/netplan/01-netcfg.yaml Replace the filename with the one present on your system.

Add the static IPv6 settings

Netplan example (replace interface name, address, prefix, gateway, and DNS with values supplied by your ISP or network admin):

network:
  version: 2
  renderer: networkd
  ethernets:
    enp0s3:
      dhcp4: no
      dhcp6: no
      addresses:
        - 2001:db8::c0ca:1eaf/64
      gateway6: 2001:db8::1
      nameservers:
        addresses:
          - 2001:4860:4860::8888
          - 2001:4860:4860::8844

Legacy /etc/network/interfaces example :

iface eth0 inet6 static
    address 2001:db8::c0ca:1eaf
    netmask 64
    gateway 2001:db8::1

Apply the changes

After saving the file, reload the network configuration.

Netplan: sudo netplan apply Legacy ifupdown: sudo ifdown eth0 && sudo ifup eth0 Replace eth0 or enp0s3 with the actual interface name.

Verify the configuration

Show the IPv6 addresses assigned to each interface: ip -6 addr show The output should list the newly configured IPv6 address under the correct interface.

Additional Notes

Replace interface identifiers ( eth0, enp0s3) with the names shown by ip a or ifconfig.

The example address 2001:db8::c0ca:1eaf/64 and gateway 2001:db8::1 are placeholders; use the values provided by your ISP or network administrator.

Ensure the prefix length (e.g., /64) matches your network’s design.

For desktop environments, the same settings can be entered via the system settings → Network panel.