Application and Protocol Support

Applies To: Windows Server 2003 with SP1

Q. Can NLB be Used For Load Balancing Terminal Server Clusters?

A. Yes. See Load balancing and terminal servers (, in the Windows Server 2003 online Help.

For detailed information about using Terminal Server Session Directory with load balancing refer to the following white paper: Session Directory and Load Balancing Using Terminal Server, (

Q. Does NLB Support WINS Resolution?

A. No, WINS names should not be automatically registered for the IP addresses configured on the NLB interface. WINS registration isn’t NLB-aware and as a result, both the dedicated and virtual IP addresses will be registered with the servers name. Note however, that the IP addresses can be mapped statically in WINS.

Q. Does NLB Support DNS Resolution?

A. NLB does not automatically register the cluster name with DNS. The administrator must directly configure the DNS server. Note however, that the IP addresses can be mapped statically in WINS.

Also note that DHCP should not be used when NLB is bound to any network adapter on a host.

Q. Can I Use L2TP/IPSec on a NLB Cluster?

A. Yes, in Windows Server 2003 NLB supports both PPTP and L2TP VPN sessions. NLB support for both PPTP and L2TP protocol requires that NLB be configured in single affinity mode. For detailed information about configuring NLB with IPSec see the following Knowledge Base article: How to Configure Network Load Balancing Server Cluster to Work with IPSec, (

Q. How Do I Configure NLB with IPSec?

A. Refer to the following Knowledge Base article: How to Configure Network Load Balancing Server Cluster to Work with IPSec, (

Q. Can I Use Kerberos with Applications Load-Balanced by NLB? How?

A. Yes.

Q. Can I Use NLB with Host Header Names?

A. Yes, ensure that all host header names are hosted by every node in the NLB cluster.

Q. Can I Use NLB with .NET Remoting?

A. .NET Remoting pipelines method invocations from client to server over a single TCP connection, meaning that once a connection is established, it is reused for subsequent method invocations and is closed only after the connection remains idle for a pre-configured amount of time. NLB can load-balance these connections, but load-balancing will likely be coarse because the unit of load-balancing is the TCP connection, not a method invocation Since one client gets pinned to a specific server, load will appear well distributed only if you have many clients connected to the cluster at the same time. Each client will get load-balanced but the connection will stay open for a very long time.

Q. When Using .NET Remoting and NLB, Method Invocations From One Client are Against the Same Host and Are Not Load-Balanced. Why?

A. See question Can I use NLB with .NET Remoting?

Q. I Use NLB to Load-Balance COM+ but Load is Not Being Distributed. Why?

A. COM+ uses connection pooling on the client, which results in method invocations that are pipelined over existing TCP connections once established. NLB load-balances TCP connections so COM+ requests are not distributed among hosts. Instead of NLB, use COM+ load-balancing which was introduced to address this issue.

Q. Can I Use NLB as a Firewall?

A. NLB is not designed to be used as a firewall. Use a certified firewall solution in front of the cluster just as you would if the hosts were not part of a cluster.

Q. Can I Load-Balance NetBIOS Traffic?

A. Yes, it is possible, though not recommended for File and Print Services. Ensure that both of the following are true:

  1. NetBIOS requires that the first IP address in TCP/IP must be used to access shares, so this must be the cluster IP address (this means you can’t have a dedicated IP address). See the KB article System Error 53 Has Occurred Using Windows NT Load Balancing Service ( for further discussion.

  2. Set the DisableStrictNameChecking registry value using the following instructions:

    • Start Registry Editor (Regedit.exe).

    • Locate and click the following key in the registry: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanmanServer\Parameters

    • On the Edit menu, click Add Value, and then add the following registry value:

      Value name: DisableStrictNameChecking

      Data type: REG_DWORD

      Radix: Decimal

      Value: 1

    • Quit Registry Editor.

    • Open a command window.

    • Run net stop server.

    • Run net start server.

This solution is documented in the KB article Connecting to SMB Share on a Windows 2000-Based Server May Not Work with an Alias Name (

For More Information

This is a preliminary document and may be changed substantially prior to final commercial release of the software described herein. The information contained in this document represents the current view of Microsoft Corporation on the issues discussed as of the date of publication. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information presented after the date of publication.