Specification RFCs
RFC 8200 – The IPv6 Specification (July 2017) that defines IPv6 as Internet Standard
RFC 2460 – The old IPv6 Specification Draft from 1998
RFC 4291 – IPv6 Addressing Architecture
RFC 5156 – Special-Use IPv6 Addresses
Security RFCs
RFC 9099 – Operational Security Considerations for IPv6 Networks (August 2021)
Websites for tests, statistics & tunnel broker
ipv6-test.com – Nice IPv6 connectivity checks and information
test-ipv6.ch – Nice IPv6 connectivity checks and information, hosted in Switzerland
www.google.com/intl/en/ipv6/statistics.html – percentage of users that access Google over IPv6 and availability of IPv6 connectivity around the world
tunnelbroker.net – Free IPv6 tunneling service by Hurricane Electric (if your ISP sucks)
Recommended Readings
Wikipedia on IPv6 – good read to get started
NIST Guidelines for the Secure Deployment of IPv6 – terrific overview of IPv6 and its Security aspects
Silvia Hagen: IPv6 Essentials / Grundlagen – recommended book to get startet with IPv6, easy to read, also available in german
Silvia Hagen: Planning for IPv6 – How to plan for IPv6 integration in your organization, aims at manager level and can be read in 2 hours
Scott Hogg / Eric Vynce: IPv6 Security – a comprehensive and competent discussion of the topic, very detailed but not updated for years