The Internet protocol version 6 (IPv6) is intended to provide many built-in benefits such as large address space, mobility, and quality of service (QoS). Because it is a new protocol and operates in some different ways than Internet protocol version 4 (IPv4), both foreseeable and unforeseeable security issues will arise. Many new functions or requirements of IPv6, i.e., automatic configuration of interfaces, mandatory Internet protocol security (IPSec), mandatory multicast, multiple Internet protocol (IP) addresses and many new rules for routing, can be abused for compromising computer systems or networks. Considering the above circumstances, Recommendation ITU-T X.1037 provides a set of technical security guides for telecommunication organizations to implement and deploy IPv6 environment. The content of this Recommendation focuses on how to securely deploy network facilities for telecommunication organizations and how to ensure security operations for the IPv6 environment.