What Is IPv6? How It Differs From IPv4 and Using It on Servers

How do you read an IPv6 address?

An IPv6 address is made up of eight groups of hexadecimal numbers separated by colons:

2001:0db8:0000:0000:0000:0000:0000:0010

Two rules make it easier to read:

1. Leading zeros in each group are dropped: 0db8 → db8, 0010 → 10.
2. A run of consecutive zero groups is replaced with :: once.

So the address above becomes 2001:db8::10. A suffix like /64 at the end of the address shows the size of the network (the prefix length). Servers usually get a /64 block; this block contains about 18 quintillion addresses and lets you use as many IPv6 addresses as you like on your server.

Special addresses you'll see often:

• ::1: The server itself (127.0.0.1 in IPv4).
• Addresses starting with fe80::: Addresses valid only on the local network link (link-local). Every network interface has one automatically.

Adding IPv6 to your domain: the AAAA record

While an A record is used for an IPv4 address, an AAAA record is used for an IPv6 address. If your server has been given an IPv6 address, add both to your domain:

yourdomain.com.    A       203.0.113.10
yourdomain.com.    AAAA    2001:db8::10

If the visitor's connection supports IPv6, the browser usually prefers IPv6; if it doesn't, it connects over IPv4. Before adding an AAAA record, test that the service on the server really works over IPv6; a broken AAAA record means visitors who use IPv6 can't reach your site. We cover DNS records in our What is DNS? article.

Checking IPv6 on a Linux server

After connecting to your server with SSH, look at your IPv6 addresses:

ip -6 addr
ip -6 route

If you see an address marked scope global and a default route (default via), IPv6 is configured. Test outbound connectivity:

ping -6 -c 4 google.com
curl -6 https://ifconfig.co

The second command shows which IPv6 address your server uses to reach the internet.

Manual configuration (Ubuntu, netplan): If your IPv6 address wasn't set up automatically, add the address and gateway your provider gave you to the configuration file under /etc/netplan/:

network:
    version: 2
    ethernets:
        eth0:
            addresses:
                - 2001:db8::10/64
            routes:
                - to: default
                  via: 2001:db8::1

Replace the interface name (eth0) and the addresses with your own details, then safely try the change with sudo netplan try; if your connection drops, the settings are rolled back automatically within a few minutes. If you lose access to the server because of a bad network setting, use your provider's web console.

IPv6 in the firewall

A firewall with rules written only for IPv4 can leave connections coming in over IPv6 unprotected. If you use ufw, check this line in the /etc/default/ufw file:

IPV6=yes

With this setting on, every rule such as sudo ufw allow 443/tcp applies to both protocols; in the sudo ufw status output, you'll see rules marked with (v6). If you changed the setting, reload the rules with sudo ufw reload.

Making services listen on IPv6

For a service to be reachable over IPv6, it also needs to listen on IPv6 addresses:

• Nginx: Add listen [::]:80; next to the listen 80; line in the server block (listen [::]:443 ssl; for HTTPS). See our How to install Nginx guide for details.
• Applications: 0.0.0.0 only listens on IPv4; an application listening on ::, on the other hand, accepts both IPv6 and IPv4 connections on most Linux systems.
• Checking: Lines like [::]:443 in the ss -tulpn output show that the service is listening on IPv6.

IPv6 on game servers

IPv6 support on game servers varies by game. Minecraft Java Edition can connect to IPv6 addresses; Bedrock Dedicated Server uses a separate port for IPv6 (19133 by default). Many Steam-based game servers, however, still work only over IPv4. Since most of your players use IPv4, always share your IPv4 address as the primary address for game servers. We cover the IPv6 setting for Bedrock in our How to make a Minecraft Bedrock server guide.

IPv6 at Nodesty

Nodesty dedicated servers come with an IPv4 address and a /64 IPv6 block, so you can run your server as dual-stack from day one and give each website, service or container its own IPv6 address. You can also get additional IPv4 addresses along with nShield DDoS protection. For questions about using IPv6 on your AMD Ryzen 9 9950X VPS plans, you can contact our support team.