.Net framework 1.1 has some problem with TCP channel in NLB.
In .Net framework 2.0, TCP channel has been enhenced to support real world network environment.
The following configuration settings are useful when configuring TCP Remoting with NLB
<channel port="xxx" ref="tcp" socketcachetimeout="0" socketcachepolicy="absoluteTimeout" />
Here is what you need to know about Microsoft supports for .Net Remoting with NLB.