I want to verify that my Ubuntu 14.04 box is secure in IPv6 space. netstat shows various things are listening on IPv6 ports. Do I have a publically reachable IPv6 address? I think not. ifconfig shows this IPv6 address:
inet6 addr: fe80::52e5:49ff:feae:3a13/64 Scope:Link
ServerFault has a useful explanation. The Scope:Link means Link-local address, something explicitly not routed and only reachable on the local Ethernet segment. This means that these servers are reachable by anything else on that same Ethernet segment, which might mean other servers in the rack in my colo. I believe all IPv6 address that start with fe80:: are link scope.
There’s a bunch of online services that will test ports or do nmap for you for IPv6.