It was not my intention to give you a hard time, but surely you must realize that to "load balance", multi-home (which is closer to your intention, I think), or bridge (unecessary, but perhaps your intention), and to do it correctly in a TCP/IP setting than every aspect of the connection is fair game as far as I am concerned.
I think you can have issues with any client connected to the internet, and there is no reason not to correct the addressing errors. This is particularly important as the MS client has evolved to essentially a pure DNS system for resolving even local names. To exclude, as you would have to, and entire Class A network because of your internal IP addressing schema strikes me at least as an odd choice.
Do a proper Class C IP addressing schema. You cannot do "load balancing" otherwise, and multi-homing the server would be a serious mistake under your schema; cf. :
Symptoms of Multihomed Browsers
Slow Computer Browsing
It is possible to have the OS to balance the network load for the computer when having several Network Adapters.
This is controlled by these DWORD values :
[HKEY_LOCAL_MACHINE \SYSTEM \CurrentControlSet \Services \NetBT \Parameters]
RandomAdapter = 1 (Disabled = 0, Enabled = 1, Default = 0)
SingleResponse = 1 (Send All = 0, Send One = 1, Default = 0)
The RandomAdapter specifies whether it should respond back with a random IP-Address (One for each adapter), or if it should respond back with the IP Address for the adapter the request was received from.
The SingleResponse says that it should only send one IP address when WINS does a name query request.
Note there is also a technology called Windows NT Load Balancing Service (WLBS - NT4) or Network Load Balacing (NBL - Win2k+), which handles clustering of several machines to act like a single unit. The cluster of several machines can provide redundancy for critical applications and higher load handling. The above registry settings does not have anything to do with this kind of service.
Note not all applications supports that the underlying TCP/IP layer responds with random IP-addresses. Instead one can try to setup Manual load balancing using the metric of the adapters:
If you are able to connect to several gateways/routers to other networks, it is possible to prioritize in which order the gateways should be searched for a certain address.
This is done by the Metric setting which is assigned to each gateway. The gateway with lowest Metric is the first to be searched(Default Gateway). Metric is the cost of using that gateway, and it will always use the one with the lowest cost first.
The metric can also be applied when having more than one network adapter, which connects to the same Network(Subnet). Example if using a wireless NIC and a standard NIC, then one can decide if it should use go through the Wireless NIC before using the Standard NIC. This is done by lowering the interface metric of the Wireless NIC.
The metric can also be used for manual load balancing between multiple network adapters:
Install TCP/IP for all adapters and assign them a different IP-address on the same subnet
If a certain adapter should be dedicated for outgoing traffic then it should be given a lower interface metric
If a certain adapter should be used for certain incomming traffic then make sure the clients connects to its IP-Address.
Note Netbios traffic (outgoing/incoming) can only be handled by a single adapter or else a name conflict will arise (Though it doesn't have to be the one dedicated for outgoing IP traffic)
Note it is possible for clients to connect to a service (FTP/HTTP,etc.) through all network adapters (To force clients to use a certain adapter one can use DNS or port blocking)
To configure the metric in Win2k/WinXP (WinNT4/Win9x can use the command "route"

:
Open Control Panel
Double click Network and Dial-up Connections(Win2k) or Network Connections(WinXP)
Righ click Local Area Connection and select Properties
Double click Internet Protocol (TCP/IP)
Press Advanced-button and it is possible to configure gateways and interface metric
Note Automatic Metric is a new feature in WinXP, which automaticly assign a metric value according to interface bandwidth (Not latency), the higher bandwidth the lower the metric. More information: