I have a Windows Server 2008 R2 machine here that is just not responding to Neighbour Solicitation requests (the IPv6 equivalent of ARP). It can see the requests, it's just chosing not to respond to them.
Wireshark sees the following request:
758 7.414264 2a01:348:6:4a6:0:15:5da1:544 ff02::1:ff00:2 ICMPv6 Neighbor solicitation
The target is clearly defined as
Target: 2a01:348:6:4a6::5 (2a01:348:6:4a6::5)
And IPConfig shows a matching local IP address (statically configured in this case)
IPv6 Address. . . . . . . . . . . : 2a01:348:6:4a6::5
So I'm at a loss as to why it's not responding.
Any ideas where I can start checking?