OPT interfaces on GRE tunnels do not accept IPv6 or IPv4 addresses to be set.
I have set up a GRE tunnel over an IPSec tunnel. I can ping the IPv4 end-points with no problem.
I have added an OPT-interface on top of the GRE-tunnel using the Interfaces>Assign menu point.
I try to set an IPv6 address on the OPT-Interface, enter 'Static IPv6' and 'CAFE:CAFE:CAFE:1::1/64' as the IPv6 address.
Click 'Save', and 'Apply'.
When I check the 'Status>Interfaces' tab, there is no corresponding entry on the OPT-interface.
Checking from the SSH-shell reveals the same thing. Does also not respond to pings.
Manually setting the IPv6 address on the OPT-interface over SSH is accepted, and the interface replies to pings. Both when started from the shell, and from the web-GUI