Subj : Re: Bye-bye Win2k.
To   : Angus Mcleod
From : Deuce
Date : Sun May 15 2005 12:48 pm

  Re: Re: Bye-bye Win2k.
  By: Angus Mcleod to Daemon on Sun May 15 2005 09:07:00

 >  >   When I set it up, I set everything to have all addresses assigned
 >  > automatically, and it was all good until a few days ago when I rebooted t
 >  > Win2K box and was surprised to see it tell me it had finished updating th
 >  > configuration... and I hadn't changed anything.
 > 
 > Uh, when you 'assign all addresses automatically', isn't that DHCP?

Not necessarily, Windows has a (patented) mechanism for assigning addresses
withOUT a central system.  They stick 'em all in the 169 subnet and just looks
for address collisions afaik.  The patent number is 6,101,499
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=
/netahtml/srchnum.htm&r=1&f=G&l=50&s1=6,101,499.WKU.&OS=PN/6,101,499&RS=PN/6,10
1,499

The abstract is as follows:
A method and computer product for automatically generating an IP network
address that facilitates simplified network connection and administration for
small-scale IP networks without IP address servers, such as those found in a
small business or home network environment. First, a proposed IP address is
generated by selecting a network identifying portion (sometimes known as an IP
network prefix) while deterministically generating the host identifying portion
based on information available to the IP host. For example, the IEEE 802
Ethernet address found in the network interface card may be used with a
deterministic hashing function to generate the host identifying portion of the
IP address. Next, the generated IP address is tested on the network to assure
that no existing IP host is using that particular IP address. If the generated
IP address already exists, then a new IP address is generated, otherwise, the
IP host will use the generated IP address to communicate over the network.
While using the generated IP address, if an IP address server subsequently
becomes available, the host will conform to IP address server protocols for
receiving an assigned IP address and gradually cease using the automatically
generated IP address. 

If using that method, if a DHCP server appears (such as the one included with
ICS) it will royally fark everything unless you explicitly release the lease
after getting rid of the DHCP server.  At which point, it will most likely
reconfig itself to the former address... but it MAY not.

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