Guides - An Overview of IPv6 on Linode

All Compute Instances are created with one IPv6 address, which is acquired by Stateless Address Autoconfiguration (SLAAC). IPv6 is fully enabled on all of Linode’s supported operating systems and uses hardware-based addressing.

Linode does not offer private IPv6 address allocations. Our IPv6 accounting was designed so that local IPv6 traffic does not count against your network transfer quota , so you can use your default IPv6 address as if it were a private IP address.

ip6tables -A INPUT -p icmpv6 -j ACCEPT
ip6tables -A FORWARD -p icmpv6 -j ACCEPT

How to Find Your IPv6 Address

You can find your Compute Instance’s IPv6 address using Cloud Manager or the ip tool with the Linux Terminal.

Using Cloud Manager

See the Viewing IP Addresses section of the Managing IP Addresses guide.

Linux Terminal

1. Using your terminal, SSH into the Compute Instance whose IPv6 address you would like to find.

   ssh user@192.0.2.0

2. Use the ip tool to find your Compute Instance’s IPv6 address:

   ip -6 address

   1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 state UNKNOWN qlen 1
       inet6 ::1/128 scope host
         valid_lft forever preferred_lft forever
   3: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
       inet6 2600:3c02::f03c:91ff:fe24:3a2f/64 scope global mngtmpaddr dynamic
         valid_lft 2591998sec preferred_lft 604798sec
       inet6 fe80::f03c:91ff:fe24:3a2f/64 scope link
         valid_lft forever preferred_lft forever

• Line 3 shows the IPv6 loopback interface, ::1/128. This is used for IPv6 traffic within the system, similar to the 127.0.0.0/8 IPv4 address block.

• Line 6 is the Compute Instance’s public IP address, 2600:3c02::f03c:91ff:fe24:3a2f/64. You can see it’s in a /64 range.

• Line 8 is the link-local IPv6 address, fe80::f03c:91ff:fe24:3a2f/64. An IPv6 link-local address is a unicast address that is automatically configured on any interface.

If your Compute Instance does not have the correct IPv6 address or any IPv6 address at all, you should verify that you have router advertisements enabled and IPv6 privacy extensions disabled. Your instance will need to accept router advertisements for SLAAC to function. These settings are properly configured by default in our supported distributions.

Additional IPv6 Addresses

If a single IPv6 address isn’t sufficient for your application, additional IPv6 addresses are provided through large address blocks, also called routed ranges or pools. From these ranges, you can manually configure individual IPv6 addresses on your Compute Instance. See the Managing IP Addresses and Manual Network Configuration on a Compute Instance guides for instructions on adding an IPv6 range and to learn how to configure it within your system.

The size of each block is identified through a prefix. These are indicated with a slash / followed by a number in base 10: the length of the network prefix in bits. This translates to the number of available addresses that are available in the range (or pool). For example, the prefix /48 contains 2^128-48 = 2⁸⁰ = 1,208,925,819,614,629,174,706,176 addresses. For an address like 2001:db8:1234::/48 the block of addresses is 2001:db8:1234:0000:0000:0000:0000:0000 to 2001:db8:1234:ffff:ffff:ffff:ffff:ffff.

The IPv6 prefixes and their respective quantity of IPv6 addresses that Linode provides are listed below.

IPv6 Routed Ranges

An IPv6 routed range is assigned to a single Compute Instance. Addresses from that range can only be configured on that instance.

• /64 routed range (18,446,744,073,709,551,616 addresses): This is the most common range provided to our customers and sufficient for most applications that require additional IPv6 addresses.
• /56 routed range (4,722,366,482,869,645,213,696 addresses): These larger ranges are typically only required by specialized systems or networking applications.

IPv6 Pools

An IPv6 pool is accessible from every Compute Instance on your account within the assigned data center. Addresses from that pool can be configured on each instance within that data center. This can enable features like IPv6 failover.

• /116 pool (4,096 addresses)

IPv6 Forwarding

If needed, IPv6 packets can be forwarded between two networks on Linode. By default, most Linux systems disable both IPv4 and IPv6 forwarding. To enable this functionality, see the IP Forwarding guide.

More Information

You may wish to consult the following resources for additional information on this topic. While these are provided in the hope that they will be useful, please note that we cannot vouch for the accuracy or timeliness of externally hosted materials.

• Understanding IP Addressing
• IPv6 and IPv4 CIDR Chart (PDF)