I don't have a public ipv4 address --> use ipv6:[https://community.synology.com/enu/forum/17/post/81256](https://community.synology.com/enu/forum/17/post/81256)

[https://macandegg.com/2021/02/synology-qnap-nas-openvpn-via-ipv6-ipv4-setup/](https://macandegg.com/2021/02/synology-qnap-nas-openvpn-via-ipv6-ipv4-setup/)