Subject: Microsoft NT4 DHCP problems with Docsis

From: "Michael W. Patrick" <[email-masked]>
Date: Fri, 9 Oct 1998 17:24:07 -0400 (EDT)

I had heard that Microsoft NT's 4.0 DHCP server"couldn't be used" in a
Docsis cable modem network and we recently discovered why.  (If this
is old news, my apologies.)

For other reasons, Service Pack 3 must be installed on the DHCP 4.0
server.  Unfortunately, the SP3 software does not correctly return the
(next) Server IP Address (siaddr) field of the BOOTP header. The
siaddr field of the BOOTP header is required by Docsis to be the IP
address of the configuration file TFTP server.  Microsoft NT SP3
documentation says that the IP value resolved for the DNS name in DHCP
option 67 "Bootfile Name" is placed into siaddr, but this doesn't work
in the shipped SP3. (Either a DNS name or dotted decimal notation may
be entered as the Option 67 value.)

This problem is documented in Microsoft Support article #Q175035
"Diskless Workstations Cannot Find BOOTP Server with DHCP".
The article calls for applying the patch "dhcpssvc.dll" on top of SP3.

Motorola has tested this patch and found it to work for Docsis
operation. We are using NT server successfully as the DHCP server
for our Docsis modem and CMTS system testing.  Our thanks to 
Ye Gu and Peter Ford of Microsoft for assistance with this problem.

Regards,
-mike

---

From: Ye Gu <[email-masked]>
Date: Fri, 9 Oct 1998 17:25:59 -0400 (EDT)

The patch that Mike mentioned below has been rolled into Microsoft
NT 4.0 Service Pack 4, which will be available shortly.

Thanks!

Ye

-----Original Message-----
From: Michael W. Patrick [mailto:[email-masked]]
Sent: Friday, October 09, 1998 2:05 PM
To: [email-masked]; [email-masked]
Cc: [email-masked]; Peter Ford; Ye Gu; [email-masked];
[email-masked]
Subject: Microsoft NT4 DHCP problems with Docsis

Regards,
-mike

---

From: Ye Gu <[email-masked]>
Date: Fri, 9 Oct 1998 19:37:09 -0400 (EDT)

First, a small correction...  The option 67 in the context of the thread
below should really be option 66 'TFTP Server Name'.

Current MS DHCP server sets BOOTP header fields ('siaddr', 'file',
'sname') as the following:
1. A DHCP client doesn't request options 66 and 67 explicitly.  DHCP
   server returns option 66 in 'siaddr' and option 67 in 'file', if these
   options have specified values and option 66 contains an IP address.
   If option 66 contains a DNS name instead, server resolves that name
   first and returns the DNS name in 'sname' and IP address in 'siaddr'.
2. A DHCP client requests options 66 and 67 explicitly.  DHCP server sets
   'siaddr', 'file', 'sname' according to step #1.  In addition, it
   returns option 66 and 67.

Cheers,

Ye

-----Original Message-----
From: Jason Schnitzer [mailto:[email-masked]]
Sent: Friday, October 09, 1998 3:23 PM
To: DOCSIS OSS Majordomo List; DOCSIS Macup Majordomo List; 'Michael W.
Patrick'
Cc: [email-masked]; Peter Ford; Ye Gu; [email-masked]
Subject: RE: Microsoft NT4 DHCP problems with Docsis

Mike,

Thanks for the info. I thought rfc2132 recommended that option 67 only be
used as a backup -- if the header's siaddr was overloaded or being used for
something else. Conceivably, a DHCP client could use both fields
(siaddr+Option67). Does the MS DHCP server support this?

Cheers,
Jason
CableLabs

> ----------
> From: 	Michael W. Patrick[SMTP:[email-masked]]
> Sent: 	Friday, October 09, 1998 3:05 PM
> Cc: 	[email-masked]; [email-masked]; [email-masked];
> [email-masked]; [email-masked]

---

From: [email-masked] (by way of Ralph Droms)
Date: Sun, 11 Oct 1998 11:37:03 -0400 (EDT)

message sent to [email-masked] by [email-masked] follows.
--------------------------------------------------------------------------
Mike,

Cheers,
Jason
CableLabs

---

From: Ye Gu <[email-masked]>
Date: Thu, 22 Oct 1998 12:12:35 -0400 (EDT)

FYI.  NT 4.0 Service Pack 4 was released on Monday and is now downloadable
from
http://www.microsoft.com/ntserver/nts/downloads/recommended/NT4SvcPk4/defaul
t.asp.

Cheers,

Ye

-----Original Message-----
From: Ye Gu 
Sent: Friday, October 09, 1998 2:14 PM
To: 'Michael W. Patrick'; [email-masked];
[email-masked]
Cc: [email-masked]; Peter Ford; [email-masked]
Subject: RE: Microsoft NT4 DHCP problems with Docsis

Thanks!

Ye

-----Original Message-----
From: Michael W. Patrick [mailto:[email-masked]]
Sent: Friday, October 09, 1998 2:05 PM
To: [email-masked]; [email-masked]
Cc: [email-masked]; Peter Ford; Ye Gu; [email-masked];
[email-masked]

Regards,
-mike