IPv6 readiness IPv6

1 ipv6 readiness

1.1 software

1.1.1 ipv4-mapped ipv6 addresses


1.2 hardware , embedded systems
1.3 shadow networks

ipv6 readiness

compatibility ipv6 networking software or firmware issue. however, of older hardware in principle upgraded replaced instead. in 2010, american registry internet numbers (arin) suggested internet servers prepared serve ipv6-only clients january 2012.

software

host software may have ipv4 or ipv6 networking software, or may support dual-stack, or hybrid dual-stack operation. majority of personal computers running recent operating system versions support ipv6. many popular applications networking capabilities compliant.

some software transitioning mechanisms outlined in rfc 4038, rfc 3493, , rfc 3542.

ipv4-mapped ipv6 addresses

hybrid dual-stack ipv6/ipv4 implementations recognize special class of addresses, ipv4-mapped ipv6 addresses. these addresses consist of 80-bit prefix of zeros, next 16 bits one, , remaining, least-significant 32 bits contain ipv4 address. these addresses typically written 96-bit prefix in standard ipv6 format, , remaining 32 bits written in customary dot-decimal notation of ipv4. example, ::ffff:192.0.2.128 represents ipv4 address 192.0.2.128. deprecated format ipv4-compatible ipv6 addresses is ::192.0.2.128.

because of significant internal differences between ipv4 , ipv6, of lower-level functionality available programmers in ipv6 stack not work same when used ipv4-mapped addresses. common ipv6 stacks not implement ipv4-mapped address feature, either because ipv6 , ipv4 stacks separate implementations (e.g., microsoft windows 2000, xp, , server 2003), or because of security concerns (openbsd). on these operating systems, program must open separate socket each ip protocol uses. on systems, e.g., linux kernel, netbsd, , freebsd, feature controlled socket option ipv6_v6only, specified in rfc 3493.

hardware , embedded systems

the cablelabs consortium published 160 mbit/s docsis 3.0 ipv6-ready specification cable modems in august 2006. docsis 2.0 updated docsis 2.0 + ipv6 provide ipv6 support, may available firmware upgrade.

shadow networks

the addition of nodes having ipv6 enabled default software manufacturer, may result in inadvertent creation of shadow networks, causing ipv6 traffic flowing networks having ipv4 security management in place. may occur operating system upgrades, when newer operating system enables ipv6 default, while older 1 did not. failing update security infrastructure accommodate ipv6 can lead ipv6 traffic bypassing it. shadow networks have occurred on business networks in enterprises replacing windows xp systems not have ipv6 stack enabled default, windows 7 systems, do. ipv6 stack implementors have therefore recommended disable ipv4 mapped addresses , instead use dual-stack network supporting both ipv4 , ipv6 necessary.