How to Configure IPv6 on Your Linux Server

Why Enable IPv6?

IPv6 provides a vastly larger address space and is increasingly required for modern applications and services. Configuring IPv6 on your Breeze ensures compatibility with IPv6-only clients and future-proofs your infrastructure.

Check Current IPv6 Status

ip -6 addr show
cat /proc/sys/net/ipv6/conf/all/disable_ipv6

If the output shows 1, IPv6 is disabled. A value of 0 means it is enabled.

Enable IPv6 if Disabled

sudo sysctl -w net.ipv6.conf.all.disable_ipv6=0
sudo sysctl -w net.ipv6.conf.default.disable_ipv6=0

Make it persistent:

echo "net.ipv6.conf.all.disable_ipv6 = 0" | sudo tee -a /etc/sysctl.conf
echo "net.ipv6.conf.default.disable_ipv6 = 0" | sudo tee -a /etc/sysctl.conf
sudo sysctl -p

Configure a Static IPv6 Address

Edit your Netplan configuration (Ubuntu 22.04+):

sudo nano /etc/netplan/01-netcfg.yaml

network:
  version: 2
  ethernets:
    eth0:
      addresses:
        - 2001:db8::1/64
      routes:
        - to: "::/0"
          via: "2001:db8::fffe"

sudo netplan apply

Test Connectivity

ping6 -c 4 ipv6.google.com
ip -6 route show

Firewall Rules for IPv6

UFW handles IPv6 automatically when IPV6=yes is set in /etc/default/ufw. Verify and reload:

sudo ufw reload
sudo ufw status

Ensure your applications bind to both IPv4 and IPv6 addresses, or use :: to listen on all interfaces.