An unexpected authentication challenge response (401/407) was received from a non-server source. T

OCS_Protocol_Stack_14429_Proxy (Rule)

An unexpected authentication challenge response (401/407) was received from a non-server source. This response will be dropped.

Knowledge Base article:

Summary

An unexpected authentication challenge response (401/407) was received from a non-server source. This response will be dropped.

Causes

This could either be clients sending challenges, or a configuration issue in the topology.

Resolutions

Please ensure that servers in the topology are talking to each other over mutually-authenticated TLS (MTLS) connections.

Element properties:

Target

Microsoft_Office_Communications_Server_2007_R2_Proxy_Server

Category

EventCollection

Enabled

False

Event_ID

14429

Event Source

OCS Protocol Stack

Alert Generate

True

Alert Severity

Error

Alert Priority

Normal

Remotable

True

Alert Message

An unexpected authentication challenge response (401/407) was received from a non-server source. This response will be dropped.

{0}

Event Log

Office Communications Server

Member Modules:

ID	Module Type	TypeId	RunAs
CollectEvent	DataSource	Microsoft.Windows.EventProvider	Default
WriteAlert	WriteAction	System.Health.GenerateAlert	Default
WriteToDB	WriteAction	Microsoft.SystemCenter.CollectEvent	Default
WriteToDW	WriteAction	Microsoft.SystemCenter.DataWarehouse.PublishEventData	Default

Source Code:

<Rule ID="OCS_Protocol_Stack_14429_Proxy" Enabled="false" Target="Microsoft_Office_Communications_Server_2007_R2_Proxy_Server" ConfirmDelivery="false" Remotable="true" Priority="Normal" DiscardLevel="100">

  <Category>EventCollection</Category>

  <DataSources>

    <DataSource ID="CollectEvent" TypeID="SCWindowsLibrary!Microsoft.Windows.EventProvider">

      <ComputerName>$Target/Host/Property[Type="SCWindowsLibrary!Microsoft.Windows.Computer"]/NetworkName$</ComputerName>

      <LogName>Office Communications Server</LogName>

      <Expression>

        <And>

          <Expression>

            <SimpleExpression>

              <ValueExpression>

                <XPathQuery Type="String">PublisherName</XPathQuery>

              </ValueExpression>

              <Operator>Equal</Operator>

              <ValueExpression>

                <Value Type="String">OCS Protocol Stack</Value>

              </ValueExpression>

            </SimpleExpression>

          </Expression>

          <Expression>

            <SimpleExpression>

              <ValueExpression>

                <XPathQuery Type="UnsignedInteger">EventDisplayNumber</XPathQuery>

              </ValueExpression>

              <Operator>Equal</Operator>

              <ValueExpression>

                <Value Type="UnsignedInteger">14429</Value>

              </ValueExpression>

            </SimpleExpression>

          </Expression>

        </And>

      </Expression>

    </DataSource>

  </DataSources>

  <WriteActions>

    <WriteAction ID="WriteToDB" TypeID="SCSystemLibrary!Microsoft.SystemCenter.CollectEvent"/>

    <WriteAction ID="WriteAlert" TypeID="SCHealth!System.Health.GenerateAlert">

      <Priority>1</Priority>

      <Severity>2</Severity>

      <AlertMessageId>$MPElement[Name="An_unexpected_authentication_challenge_response__401_407__was_received_from_a_non_server_source___This_response_will_be_dropped_"]$</AlertMessageId>

      <AlertParameters>

        <AlertParameter1>$Data/EventDescription$</AlertParameter1>

      </AlertParameters>

      <Suppression>

        <SuppressionValue>$Data/EventDisplayNumber$</SuppressionValue>

        <SuppressionValue>$Data/PublisherName$</SuppressionValue>

      </Suppression>

    </WriteAction>

    <WriteAction ID="WriteToDW" TypeID="SCDataWarehouseLibrary!Microsoft.SystemCenter.DataWarehouse.PublishEventData"/>

  </WriteActions>

</Rule>