Network configuration and management

Dual stack env. may introduce confusion
"telnet localhost" does not work, when the client only tries 127.0.0.1 and the server only accepts ::1.
source address selection is more complicated
(e.g.) mismatches of BGP peer addresses can happen.
DNS PTR RRs
we cannot pre-register all IPv6 addresses in a subnet;
"dhcp101.kame.net" doesn't work for IPv6.
Scoped addresses
(e.g.) link-locals are very useful for operation, but the notion is very confusing;
novice operators often forget disambiguating the link.