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NLB detected duplicate cluster subnets

Microsoft.Windows.NetworkLoadBalancing.10.0.NLB.detected.duplicate.cluster.subnets (Rule)

Knowledge Base article:

Summary

Hosts in a Network Load Balancing (NLB) cluster are configured to load balance network traffic. Host configuration is set by using NLB Manager, and if it is not configured properly, the NLB cluster may not function correctly

Resolutions

Restart the NLB cluster

If Network Load Balancing (NLB) detects that there are duplicate subnets in the cluster, it may be due to network partitioning, which prevents NLB heartbeats of one or more hosts from reaching the other cluster hosts. You  may need to restart the NLB cluster to resolve this issue.

To restart the NLB cluster:

You can also reload the configuration and restart the cluster node using the links below:

Reload configuration

Stop NLB node

Start NLB node

Element properties:

TargetMicrosoft.Windows.NetworkLoadBalancing.10.0.ServerRole
CategoryAlert
EnabledTrue
Alert GenerateFalse
RemotableTrue

Member Modules:

ID Module Type TypeId RunAs 
DS DataSource Microsoft.Windows.NetworkLoadBalancing.EventProvider Default
WA WriteAction Microsoft.Windows.NetworkLoadBalancing.10.0.GenerateAlert.SuppressByDescription Default
WriteToDB WriteAction Microsoft.Windows.NetworkLoadBalancing.10.0.CollectEvent Default

Source Code:

<Rule ID="Microsoft.Windows.NetworkLoadBalancing.10.0.NLB.detected.duplicate.cluster.subnets" Enabled="true" Target="Microsoft.Windows.NetworkLoadBalancing.10.0.ServerRole" ConfirmDelivery="true" Remotable="true" Priority="Normal" DiscardLevel="100">

  <Category>Alert</Category>

  <DataSources>

    <DataSource ID="DS" TypeID="NLBLibrary!Microsoft.Windows.NetworkLoadBalancing.EventProvider">

      <Criteria>

        <SimpleExpression>

          <ValueExpression>

            <XPathQuery>EventDisplayNumber</XPathQuery>

          </ValueExpression>

          <Operator>Equal</Operator>

          <ValueExpression>

            <Value>18</Value>

          </ValueExpression>

        </SimpleExpression>

      </Criteria>

    </DataSource>

  </DataSources>

  <WriteActions>

    <WriteAction ID="WA" TypeID="Microsoft.Windows.NetworkLoadBalancing.10.0.GenerateAlert.SuppressByDescription">

      <Priority>1</Priority>

      <Severity>1</Severity>

      <AlertMessageId>$MPElement[Name="Microsoft.Windows.NetworkLoadBalancing.10.0.NLB.detected.duplicate.cluster.subnets.AlertMessage"]$</AlertMessageId>

      <EnableAlert>true</EnableAlert>

    </WriteAction>

    <WriteAction ID="WriteToDB" TypeID="Microsoft.Windows.NetworkLoadBalancing.10.0.CollectEvent">

      <CollectEvent>false</CollectEvent>

    </WriteAction>

  </WriteActions>

</Rule>