With IPv6 privacy extensions, you don't magically get an address starting with
2001::. Instead, the starting of the IPv6 address will be the what you get from your ISP.
You'll still use the prefix of the IPv6 address that's been assigned to you. However, the suffix (the 2nd part) will be randomly generated, instead of being based on your MAC address.
If you run
ip -6 addr, you should see that there are several non-
fe80:: addresses for your main interface. These addresses should have the same global prefix (typically, the first four parts of the address). If so, this means that IPv6 privacy extensions are working.
You can also identify by looking at the end of each IPv6 address printed with
ip -6 addr. Any link local IPv6 address line ends with a suffix of
scope link, each global static ends with suffix
scope global static, each from SLAAC ends with suffix
scope global dynamic, each private extension address ends with suffix
scope global temporary dynamic and expired with
scope global temporary deprecated.
Also, note that the
2001:db8/32 has been designated for use in documentation only.