IPv6

IPv6 has been developed to future proof the Internet by replacing IPv4 which is running out of addresses [bbc.com⧉]. As "IPv6 the only option for sustainable growth" [sidn.nl⧉] more governments and customers are starting to make IPv6 support a requirement to prepare for the future.

After in Q3 2022 Amazon AWS released IPv6 support for all services used by Cirrus, in December 2022 Cirrus migrated to a dual-stack solution (IPv4+IPv6):

• Keep IPv4 support for all customers and users that have not adopted IPv6 yet.
  and
• Add IPv6 support for customers and users that (also) support IPv6.

Impact

Your end users should not notice anything in a dual-stack solution:

• If your users or networks do not have IPv6 support nothing will change
• If your users or networks also have IPv6 support they will start using IPv6
• If your users or networks only have IPv6 support they will now be able to use Cirrus.

Except that with IPv6 the IP address they use changes, this normally completely hidden, except e.g. for Invigilators where it is shown in the Invigilation log:

• IPv4 addresses look like 172.16.254.1; four 0-255 numbers separated by dots (.).

• IPv6 addresses look like 2001:db8::ff00:42:8329; upto 8 groups separated by colons : of four hexadecimal digits (0-9a-f), where leading zeros can be omitted.

IP whitelisting should not be in place, as Cirrus on Amazon AWS uses many different IP addresses, but if it were, it would of course be impacted as IPv6 uses different IP addresses.

Test IPv6 / network

There are plenty of online test sites available to test IPv6 connectivity and warn of issues in the visitor's IPv6 configuration, e.g.:

• https://ipv6-test.com/ ⧉
• https://ipv6test.google.com/ ⧉

In case your organisation (or user's ISP) has only recently add IPv6 support, it would be wise to run a test using one of these websites. Furthermore if you have subscribed to a Cirrus RC environment also run a test there as the ultimate test.