IPv6 Interview Questions and critic

Tue Aug 27 18:43:38 UTC 2002

On Tuesday, August 27, 2002, at 10:41  AM, Joe Baptista wrote:

> Ipv6 uses 128 bits to provide addressing, routing and identification
> information on a computer. The 128-bits are divided into the left-64 
> and
> the right-64.  Ipv6 uses the right 64 bits to store an IEEE defined 
> global
> identifier (EUI64). This identifier is composed of company id value
> assigned to a manufacturer by the IEEE Registration Authority. The 
> 64-bit
> identifier is a concatenation of the 24-bit company_id value and a 
> 40-bit
> extension identifier assigned by the organization with that company_id
> assignment. The 48-bit MAC address of your network interface card is 
> also
> used to make up the EUI64.

Since it so easy for a host (relative to ipv4) to have multiple ip 
addresses, I like what Microsoft has done. If told by a router, a Win 
XP box will assign itself a global unicast address using EUI-64. It 
will also create a global unicast anonymous address. This will not be 
tied to the hardware, and the OS will also limit how long it uses that 
address before deprecating that address and creating a new preferred 
anonymous address. I can see servers using the EUI-64 address, while 
clients use the anonymous address. It will allow servers to narrow down 
who is accessing their servers to a 64 bit subnet. That will be good 
enough for most statistics, but will make it more difficult to do the 
scarier tracking of users.

I have noticed that the Linux and Mac OS X ipv6 implementations so not 
create the private addresses automatically.
Peter Hill
Network Engineer
Carnegie Mellon University