All the IPv4 blocks have already fully allocated, and IPv4 should be exhausted any time from now. Although the Internet transition from IPv4 to IPv6 has been prolonged, it is advisable to make use of IPv6 now in parallel with IPv4.
In fact, many websites are found to be faster when accessed using IPv6.
Below are my settings on IPv6 for TM UniFi for your reference:
- Connection type: Native
- Interface: PPP
- DHCP-PD: Enable
- Release prefix on exit: Enable
- Auto Configuration Setting: Stateless
- Connect to DNS Server automatically: Disable (you can choose Enable to use the DNS servers of TM UniFi)
- IPv6 DNS Server: you can choose to use any of the public DNS servers below:
- Google: 2001:4860:4860::8888, 2001:4860:4860::8844
- OpenDNS: 2620:0:ccc::2, 2620:0:ccd::2
- CloudFlare: 2606:4700:4700:0:0:0:0:1111, 2606:4700:4700:0:0:0:0:1001
- UncensoredDNS: 2001:67c:28a4::, 2a01:3a0:53:53::
- Enable Router Advertisement: Enable