Disable Windows IPv6 Temporary Addresses
The default Microsoft Windows IPv6 implementation has privacy extensions enabled, where IPv6 temporary addresses are used for client activities.
The idea is that IPv6 has so many addresses available to it that we can create extra ones to help mask our activities. In practice these temporary addresses are largely pointless, and are very unhelpful if firewalls and ACLs are configured to allow access from a specific static address.
To disable IPv6 temporary addresses type these commands into an administrator-level PowerShell or Command Prompt and then restart your PC:
netsh interface ipv6 set global randomizeidentifiers=disabled netsh interface ipv6 set privacy state=disabled netsh interface teredo set state disable