Microsoft KB Archive/313579

= Windows 2000 does not provide proxy ARP for off-subnet IP addresses =

Article ID: 313579

Article Last Modified on 2/28/2007

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APPLIES TO


 * Microsoft Windows 2000 Server
 * Microsoft Windows 2000 Advanced Server

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This article was previously published under Q313579



SYMPTOMS
Microsoft Windows 2000 does not provide the proxy Address Resolution Protocol (ARP) for off-subnet IP addresses. If you use Network Load Balancing (NLB) to distribute clients among several servers that are running Routing and Remote Access, and if all the LAN interfaces on the servers are connected to the same router, you cannot use routes to route packets back to the remote access clients. This behavior occurs because clients may connect to different servers that are running Routing and Remote Access for load balancing but always receive IP addresses from the same subnet.



RESOLUTION
To work around this behavior, use one of the following methods:
 * Implement IP pools from different subnets on each server that is running Routing and Remote Access, and then set routes on the LAN router for each IP pool.
 * If you cannot use the first method, add an IP address from the remote access client IP pool to the LAN interface of each server that is running Routing and Remote Access. The server can provide proxy ARP for the off-subnet clients because this address pool does not appear as being off of the subnet.



STATUS
This behavior is by design.



MORE INFORMATION
Sometimes, you may want to use proxy ARP for off-subnet IP pools on servers that are running Routing and Remote Access in Windows 2000. For example, the server is distributing IP addresses to clients that are not in the same subnet as the LAN interface for the server that is running Routing and Remote Access, and all servers are distributing addresses from the same subnet.

Keywords: kbenv kbnetwork kbprb KB313579

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