If you see any problem with NET TCP Service, You can use following config to debug NET TCP problems

On 64 bit machines, you have to add this info to C:\WINDOWS\Microsoft.NET\Framework64\v3.0\Windows Communication Foundation\SMSvcHost.exe.config

On 32 bit machines, you have to add this info to C:\WINDOWS\Microsoft.NET\Framework\v3.0\Windows Communication Foundation\SMSvcHost.exe.config

<?xml version="1.0" encoding="utf-8"?>
<!-- The configuration file for SMSvcHost.exe -->
<configuration>
    <runtime>
        <gcConcurrent enabled="false" />
        <generatePublisherEvidence enabled="false" />
    </runtime>
    <!-- Below are some sample config settings:   
    <system.serviceModel.activation>
        <net.tcp listenBacklog="10" maxPendingConnections="100" maxPendingAccepts="2" receiveTimeout="00:00:10" teredoEnabled="false">
            <allowAccounts>
                // LocalSystem account
                <add securityIdentifier="S-1-5-18"/>

                // LocalService account
                <add securityIdentifier="S-1-5-19"/>
               
                // Administrators account
                <add securityIdentifier="S-1-5-20"/>
               
                // Network Service account
                <add securityIdentifier="S-1-5-32-544" />
               
                // IIS_IUSRS account (Vista only)
                <add securityIdentifier="S-1-5-32-568"/>
            </allowAccounts>
        </net.tcp>
        <net.pipe maxPendingConnections="100" maxPendingAccepts="2" receiveTimeout="00:00:10">
            <allowAccounts>
                // LocalSystem account
                <add securityIdentifier="S-1-5-18"/>

                // LocalService account
                <add securityIdentifier="S-1-5-19"/>
               
                // Administrators account
                <add securityIdentifier="S-1-5-20"/>
               
                // Network Service account
                <add securityIdentifier="S-1-5-32-544" />
               
                // IIS_IUSRS account (Vista only)
                <add securityIdentifier="S-1-5-32-568"/>
            </allowAccounts>
        </net.pipe>
        <diagnostics performanceCountersEnabled="true" />
    </system.serviceModel.activation>
    -->

  <system.diagnostics>
    <sources>
      <source name="SMSvcHost" switchValue="Verbose">
        <listeners>
          <add type="System.Diagnostics.DefaultTraceListener" name="Default">
            <filter type="" />
          </add>
          <add name="xml">
            <filter type="" />
          </add>
        </listeners>
      </source>
      <source name="System.ServiceModel.MessageLogging" switchValue="Verbose,ActivityTracing">
        <listeners>
          <add type="System.Diagnostics.DefaultTraceListener" name="Default">
            <filter type="" />
          </add>
          <add name="ServiceModelMessageLoggingListener">
            <filter type="" />
          </add>
        </listeners>
      </source>
      <source name="System.ServiceModel" switchValue="Verbose,ActivityTracing"
        propagateActivity="true">
        <listeners>
          <add type="System.Diagnostics.DefaultTraceListener" name="Default">
            <filter type="" />
          </add>
          <add name="ServiceModelTraceListener">
            <filter type="" />
          </add>
        </listeners>
      </source>
    </sources>
    <sharedListeners>
      <add initializeData="C:\customers\smsvchost.e2e" type="System.Diagnostics.XmlWriterTraceListener, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
        name="xml" traceOutputOptions="LogicalOperationStack, DateTime, Timestamp, ProcessId, ThreadId, Callstack">
        <filter type="" />
      </add>
      <add initializeData="C:\customers\SMSvcHost_messages.svclog"
        type="System.Diagnostics.XmlWriterTraceListener, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
        name="ServiceModelMessageLoggingListener" traceOutputOptions="LogicalOperationStack, DateTime, Timestamp, ProcessId, ThreadId, Callstack">
        <filter type="" />
      </add>
      <add initializeData="C:\customers\SMSvcHost_tracelog.svclog"
        type="System.Diagnostics.XmlWriterTraceListener, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
        name="ServiceModelTraceListener" traceOutputOptions="LogicalOperationStack, DateTime, Timestamp, ProcessId, ThreadId, Callstack">
        <filter type="" />
      </add>
    </sharedListeners>
    <trace autoflush="true" />
  </system.diagnostics>

  <system.serviceModel>
    <diagnostics>
      <messageLogging logEntireMessage="true" logMalformedMessages="true"
        logMessagesAtServiceLevel="true" logMessagesAtTransportLevel="true" />
    </diagnostics>
  </system.serviceModel>
</configuration>