DHCP Event ID 1002: DHCP Received an Unknown Option...

Last reviewed: March 5, 1998
Article ID: Q181024

The information in this article applies to:

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

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 more information, see the following article in the Microsoft Knowledge base:

   ARTICLE-ID: Q160699
   TITLE     : Understanding DHCP IP Address Assignment for RAS Clients

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

Pipeline routers are manufactured by Ascend, a vendor independent of Microsoft; we make no warranty, implied or otherwise, regarding this product's performance or reliability.

For information about how to contact Ascend, query in the Knowledge Base for one of the following articles:

   ARTICLE-ID: Q65416
   TITLE     : Hardware and Software Third-Party Vendor Contact List, A-K

   ARTICLE-ID: Q60781
   TITLE     : Hardware and Software Third-Party Vendor Contact List, L-P

   ARTICLE-ID: Q60782
   TITLE     : Hardware and Software Third-Party Vendor Contact List, Q-Z

Keywords          : NTINTEROP ntnetserv ntrouter NTSrvWkst nttcp kb3rdparty kberrmsg kbinterop kbnetwork
Version           : WinNT:3.51,4.0
Platform          : winnt
Issue type        : kbprb

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Last reviewed: March 5, 1998
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