DOCUMENT:Q181024  10-AUG-2001  [winnt]
TITLE   :DHCP Event ID 1002: DHCP Received an Unknown Option...
PRODUCT :Microsoft Windows NT
PROD/VER:winnt:3.51,4.0
OPER/SYS:
KEYWORDS:kb3rdparty kberrmsg kbinterop kbnetwork

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The information in this article applies to:

 - Microsoft Windows NT Workstation versions 3.51, 4.0 
 - Microsoft Windows NT Server versions 3.51, 4.0 
 - Microsoft Routing and Remote Access Service Update for Windows NT Server version 4.0 
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SYMPTOMS
========

Your Windows NT Remote Access Service (RAS) server or Routing and Remote Access
Service (RRAS) server may log the following event message in Event Viewer about
once every minute:

   Event ID   : 1002
   Source     : DHCP
   Description: DHCP received an unknown option 006 of length 007. The raw
                option data is given below.

CAUSE
=====

This error is usually caused when the following conditions exist:

 - Your Windows NT RAS server is configured to use Dynamic Host Configuration
   Protocol (DHCP) to assign remote TCP/IP client addresses.

 - You have a router on your network with a feature known as DHCP Spoofing
   enabled.

 - You do not have a DHCP server currently on your network.

RESOLUTION
==========

To resolve this issue, you will need to do one of the following:

 - Configure your RAS server to statically assign IP address using the following
   steps:

   1. Click Start, point to Settings, click Control Panel, and double-click
      Network.

   2. Click the Services tab and double-click Remote Access Service.

   3. Click Network, click Configure for TCP/IP in Server Settings of the
      Network Configuration dialog box.

   4. Click Use Static Address Pool and enter the IP address pool that you want
      to use.

   5. Click OK and close until you are prompted to restart your computer.

   6. Restart your computer.

   -or-

 - Disable the DHCP Spoofing feature on your router. Consult your router
   manufacturer for information on how to do this.

   -or-

 - Configure a DHCP server on your network.

MORE INFORMATION
================

With a default installation, a Windows NT RAS server is configured with the
option to "Use DHCP to assign remote TCP/IP client addresses." With this option
set, the RAS server will broadcast DHCPDISCOVER packets to a DHCP server. After
the DHCP server responds, the RAS server will cache a range of IP addresses for
its dial-in clients. What are not cached are the other configuration options
such as Domain Name Service (DNS) servers, Windows Internet Name Service (WINS)
servers, and default gateway information.

For additional information, click the article number below to view the article in
the Microsoft Knowledge Base:

   Q160699 Understanding DHCP IP Address Assignment for RAS Clients

Some routers, including Ascend Pipeline routers, have a feature known as DHCP
Spoofing.

NOTE: Ascend Corporation has been purchased by Lucent Technologies, Inc.

This feature is essentially similar to a DHCP Relay Agent. The router will listen
for DHCP broadcasts and attempt to answer the requests by responding with a
temporary IP address, along with other optional parameters that are
pre-configured in the router.

The temporary IP address is the IP address of the router plus 1 for each
sequential client request. A client who receives an address from the router will
have a lease duration of only 1 minute and will have to renew its address after
the lease expires in 50 percent of its lease time.

The third-party products discussed in this article are manufactured by vendors
independent of Microsoft; we make no warranty, implied or otherwise, regarding
these products' performance or reliability.

For additional information about how to contact the manufacturer, click the
article numbers below to view the articles in the Microsoft Knowledge Base:

   Q65416 Hardware and Software Third-Party Vendor Contact List, A-K

   Q60781 Hardware and Software Third-Party Vendor Contact List, L-P

Additional query words:

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Keywords          : kb3rdparty kberrmsg kbinterop kbnetwork 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT351search kbWinNT400search kbWinNTW351search kbWinNTW351 kbWinNTSsearch kbWinNTS400search kbWinNTS400 kbWinNTS351 kbWinNTS351search kbAudDeveloper kbRRASNTSearch kbRRASNT400
Version           : winnt:3.51,4.0
Issue type        : kbprb

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Copyright Microsoft Corporation 2001.