# How To Configure IPv6 on CentOS 7

### Introduction

In this guide, you will configure IPv6 support on your TeraSwitch VPS. This will allow it to communicate across the internet using the latest standards.

## Prerequisites

Before you begin this guide you'll need the following:

- One Linux VPS running CentOS 7

## Step 1 — Locating the Address

To start, you need to locate the IPv6 address that was automatically assigned to your server. Login to your TeraSwitch portal at [https://my.teraswitch.com/clientarea.php](https://my.teraswitch.com/clientarea.php).

From the top menu bar, navigate to **Services** > **My Services**, and then choose the VPS you would like to configure.

Next, scroll down to **Interfaces** and look for **Fixed IP Address**. You will see at least two addresses. The longer one is your **IPv6 address** for this specific server.

For example, the IPv6 address for your server might look similar to this: `2607:fdc0:2:0:f816:3eff:fea6:2734`

## Step 2 — Calculating the Gateway

CentOS will also need to know the location of the **default gateway** in order to sucessfully send traffic outside the network. At TeraSwitch, this will always be the address ending in `...0000:0000:0000:0001`.

In IPv6, we can compress all of those zeroes, and rewrite the ending like this: `::1`

So for example:
| <!-- --> | <!-- --> |
| ----------- | -------------- |
| If your **IPv6 address** is: | `2607:fdc0:2:0:f816:3eff:fea6:2734` |
| Your **default gateway** is: | `2607:fdc0:2:0::1` |

## Step 3 — Applying the Configuration

In this step you will insert the address and gateway into CentOS's configuration.

To do this, connect to your server, and then open the `/etc/sysconfig/network-scripts/ifcfg-eth0` file with root privileges:

sudo nano /etc/sysconfig/network-scripts/ifcfg-eth0

At the bottom of this file, add the following lines, replacing **your_ipv6_address** and **your_ip_gateway** with the values you located in the previous steps.

IPV6INIT=yes
IPV6ADDR=your_ip_address
IPV6_DEFAULTGW=your_ip_gateway

## Step 4 — Restarting the `network` service

Finally, in CentOS we can restart the network by running the following command:

sudo systemctl restart network

Your terminal session will briefly pause while your VPS's network goes down and comes back online.

Verify that you can ping IPv6 addresses:

 ping6 2606:4700:4700::1111

You'll see the following output:

PING 2606:4700:4700::1111(2606:4700:4700::1111) 56 data bytes
64 bytes from 2606:4700:4700::1111: icmp_seq=1 ttl=60 time=0.535 ms
64 bytes from 2606:4700:4700::1111: icmp_seq=2 ttl=60 time=0.300 ms
64 bytes from 2606:4700:4700::1111: icmp_seq=3 ttl=60 time=0.314 ms

You can also list the default route for IPv6 traffic:

/sbin/ip -6 route show

You'll see the following output:

2607:fdc0:2::/64 proto kernel metric 256 pref medium
fe80::/64 proto kernel metric 256 pref medium
default via 2607:fdc0:2::1 metric 1 pref medium

## Conclusion

In this article you enabled IPv6 support for your VPS, future-proofing it for next generation applications.

Next, consider double checking that any firewall rules you may have are also configured for IPv6.