Re: NT 3.51 behavior

[Shawn Mamros <[e-mail]>]

>I am using Microsoft NT 3.51 as a DHCP client to talk to our
>server.  Everything seems to be working fine but in the Event Log,
>I am getting this "warning" message:
>
>---
>DHCP received an unknown option 012 of length 009.  The
>raw option data is given below.
>---
>
>The raw data actually shows the hostname returned by
>the server which happens to be 9 bytes long.  Option 12
>is the hostname tag (assuming 012 is in decimal and not octal).
>Has anyone seen something like this with NT 3.51?  What is
>the cause of this warning?

I'm not certain, but I can make a semi-educated guess...

The NT DHCP client (and all Microsoft DHCP clients) actually use option 12
to transmit the client's hostname *to* the server.  (Take a network trace
sometime and see for yourself...)  All machines running Microsoft networking,
even DHCP clients, require that a hostname be set when the system is
installed.  Microsoft's NT DHCP server, in turn, can use this hostname,
coupled with the IP address it provides, to update the WINS server database
(which, in turn, can feed into an MS NT DNS server, thus providing their
own form of dynamically updateable DNS).

Because of this, there is no reason for their DHCP client to use a
DHCP server-specified hostname (via option 12).  I don't know why they
felt that justified putting in a warning message, but they did...

There's nothing in the DHCP specs that prohibits the use of option 12
in this manner, though it may seem a little "odd".

(Any MS folks, feel free to point out any inaccuracies in the above...)

-Shawn Mamros
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