How do I know which IPv6 prefix length has been assigned by the provider?

[defaultuserfoo]

How do I know which IPv6 prefix length has been assigned by the provider?

[Patrick M. Hausen]

Ask the provider?

[defaultuserfoo]

Is there no other way?

It seems that other routers figure it out automatically.  Or not?

[meyergru]

Interfaces :: Overview -> WAN, check details with the magnifying glass. See attachment.

[defaultuserfoo]

Thanks!  Are you sure the information shown on that page is true?  It seems to me it depends on what you set as prefix length for the interface yourself, not what your ISP actually gives you.