SP and mixed IPv6/IPv4 addresses

[Tom Poage]

Interesting case brought to my attention.

Institution uses both IPv6 and IPv4. Internal client (multiple
interfaces) authenticates against IdP via IPv6, but external
communication (to remote SP) is via IPv4. Triggers checkAddress error.
Not quite the proxy scenario in the error message.

Certainly, checkAddress can be set false, but I also wonder whether
we'll start to see this kind of error more often as the world continues
to adopt IPv6.

Tom.