Here are some things you can't yet do with IPv6:
- PXE Boot: There is no Preboot eXecutable Environment boot standard for IPv6 yet, but there are some developments towards this goal. PXE v2.1 is a 1999 non-open standard, and it appears to me the momentum is to move away from the PXE standard and add other abilities to network boot such as HTTP, iSCSI and other alternative file transport and the ability for one network boot standard to work with multiple architectures.
- Intel's response to this subject indicates they expect network IPv6 booting to be done via UEFI. I am seeing UEFI BIOS in newer business x86-64 workstations, but I do not know if they are currently capable of IPv6 remote boot. UEFI options I've seen are disabled by default in BIOS.
- What used to be etherboot—an open-source network boot firmware / chain-loadable boot program—became gPXE, and in 2010 it forked into gPXE and iPXE. iPXE's site says all new development is being done on iPXE, but there was a Google Summer of Code project to add IPv6 boot to gPXE, so I am currently confused as to which project to try first if I were prototyping IPv6 network booting.
- In my view, dual-stack IPv6-IPv4 networking will be a reality for at least several years, so I expect IPv4 PXE boot to be the norm until IPv6 network boot standards are mature.
- NAT: Network Address Translation was created to slow down IPv4 address exhaustion, so it is not needed for IPv6. However, many users seem to think that NAT enhances security (I largely disagree), and some have tried to develop a form of NAT during the IPv4-to-IPv6 transition phase so a group of IPv4-only hosts might communicate over a NAT device with IPv6-only hosts. But the transition NAT attempts have run into problems and aren't considered general-purpose transition solutions. Ideally all hosts on the internet can directly address each other, so NAT should disappear when IPv4 does.
- WINS: Windows Internet Name Service maps NetBIOS names to IPv4 addresses, but Microsoft has moved to DNS for client-server name resolution and is developing PNRP for peer name resolution. Do not expect WINS to be implemented for IPv6 name resolution or to use IPv6 to transport queries.
Original article published February 1, 2010, 10:00 AM, later edited for updates.