Hi Leung,

Pega software does not use IP addresses directly, but instead uses name resolution to communicate between servers running Pega software.  As long as the DNS Server in the  your environment is providing proper name resolution, the process of accessing remote addresses is transparent to Pega software.  Therefore, all features of Pega software do support and should be operational in both an IPv4 and IPv6 environments. 

(From Wikipedia:

Internet Protocol version 6 (IPv6) is the latest revision of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet. IPv6 was developed by the Internet Engineering Task Force (IETF) to deal with the long-anticipated problem of IPv4 address exhaustion.)

IPv6 can make Ignite clustering unstable if you do not have full support for IPv6 in your network... I used this guide to disable it from the Ignite servers and Pega nodes:

https://giritharan.com/disable-ipv6/

You will also need to disable the Teredo tunneling interface, as Pega advertises this through Ignite, even though it is an "inactive" tunneling interface. It causes Ignite clustering to fail since it cannot connect to these invalid IPv6 autoconfiguration addresses.

https://lonesysadmin.net/2011/04/25/how-to-disable-teredo-ipv6-tunneling-in-microsoft-windows/

netsh interface teredo set state disabled