Added comments, removed ifdef IPV6.
Added comments, removed ifdef IPV6.

FossilOrigin-Name: 6e11ca7d6230d67587a9f3c77ccadb81f80c36b08344555ea75c36473dfc0441
7u83/actube,7u83/actube,7u83/actube,7u83/actube,7u83/actube