We help IT Professionals succeed at work.

Multi NIC card and one IP address

Hi all

Can I install several NIC card on the same machine and have load balancer and Fail over mechanism (between the card) while the outside world see them as one IP address?

I need it on the following machines:

Watch Question

IT Architect/Technology Delivery Manager
I don't know for sure about the other operating systems but on NT you can get software that will do this for you from Intel if your using an Intel nic. I think 3Com also supports this with their nics also.
From the Microsoft website...

Assume that you have this setup: all clients have equal network access to any of the NICs on the multihomed computer. Let all of the client's and server's NICs be on the same subnet. A client sends out a broadcast name query. This request will be received by all of the server's adapters. All of the server's adapters will respond to the client's query and each server adapter's response will contain only one returned address: its own. The client connects with the first adapter to respond and the client drops response packets from the server's other adapters.

Now consider with Load Balancing as you requested:

as was the case above; Clients have equal access to all of the server's NICs, and all clients and server NICs are on the same subnet. Here you can help to distribute the client connections between the server NICs by enabling the RandomAdapter in the Registry. In this way, each NIC will still respond to the name query, but each NIC will choose the IP address randomly from all the NICs on the server. This helps to distribute network sessions among the NICs, but does not necessarily balance the load since network traffic may vary greatly between the sessions.

WARNING: Using Registry Editor incorrectly can cause serious, system-wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of Registry Editor can be solved. Use this tool at your own risk.

To do this, you will need to add the parameter RandomAdapter under the following subkey:


For additional information, please see the following article in the Microsoft Knowledge Base:

Q120642 TCP/IP & NBT Configuration Parameters for Windows NT


The most efficient way, along with the most reliable way is to use NIC's made to do what your asking.  I use Intel server nic's to do this and have had great success, you can unplug one cable and you don't lose a single packet.
This old question needs to be finalized -- accept an answer, split points, or get a refund.  For information on your options, please click here-> http:/help/closing.jsp#1 
Post your closing recommendations!  No comment means you don't care.

Explore More ContentExplore courses, solutions, and other research materials related to this topic.