Details of stateless autoconfiguration address space is split in two 64bit halves upper 64bit are used to specify a particular network segment lower 64bit are used for individual nodes in one segment lower 64bit are generated from 48bit mac address with 'fffe' in the middle potential problem: privacy DNS and IPv6 forward resolval (hostname -> address) ipv4 uses 'IN A' record ipv6 uses 'IN AAAA' record a particular hostname can have A and AAAA records reverse resolval uses .ip6.arpa. suffix uses hexadecimal instead of decimal notation: 4.4.0.0.0.0.0.0.0.8.7.0.1.0.0.2.ip6.arpa. portable applications under *BSD/Linux do round-robin between all records, with a preference of ipv6 for the first try. BSD Sockets API and IPv6 struct in_addr has become in6_addr new API's like getaddrinfo() instead of gethostbyname() support _both_ ipv4 and ipv6 apart from that, everything is the same. configuration under linux router/gateway runs radvd or zebra for sending router advertisements client just has to load 'ipv6' module and configure an interface up recevies prefix-advertisement(s) and auto-configures address accordingly IPv6 specific security issues packet filter has to explicitly allow neighbour discovery, since it's inside ipv6/icmpv6 special attention to option headers most sites won't want routing or hop-by-hop options neighbour cache DoS: compare with existing neighbour cache issues in large (/16) networks in ipv6, the standard is /64 for every segment (!) one advantage: port scanning of whole networks way more difficult :)