Playing in one of my (V)LANs without global reachability.
Couple days ago I had a router advertising IPv6 global prefix
8888::0/64 EUI-64 -- then I recycled that box to elsewere, and
put another box with different advertisement prefix.
The old one doesn't seem to disappear...
$ /sbin/ifconfig vlan0003
vlan0003 Link encap:Ethernet HWaddr 00:10:4B:6B:BE:C0
inet6 addr: 3ffe:2610:2:fff0:210:4bff:fe6b:bec0/64 Scope:Global
inet6 addr: 8888::210:4bff:fe6b:bec0/64 Scope:Global
inet6 addr: fe80::210:4bff:fe6b:bec0/10 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1