Scoped IPv6 address

IPv6 has address scopes, but site-local have vanished
link-local, or global

With link-local, need to identify "which scope we are using" to disambiguate
sin6_scope_id

Do not try to fill sin6_scope_id by yourself - it is implementation-dependent
getpeername, getsockname, getaddrinfo

Textual representation: fe80::1%de0
But users should really use DNS names!

"ping6 -w", LLMNR (multicast DNS)