Failure to contact domain controller monitor.

Microsoft.Windows.DfsReplication.DCUnreachableMonitor (UnitMonitor)

This monitor checks whether the DFS Replication service on the monitored computer was able to contact a domain controller to retrieve configuration information.

Knowledge Base article:

Summary

The DFS Replication service may register this event if it failed to contact the specified domain controller to access configuration information. Replication will be stopped until fresh configuration information can be retrieved from the domain controller. The service will try to retrieve configuration information again during the next polling cycle.

Event: 1202

Anti-event: 1206, 1004, 1104

Causes

The DFS Replication service was unable to contact the specified domain controller to obtain new configuration information. This issue may be caused by TCP/IP connectivity, firewall, Active Directory Domain Services (AD DS), or DNS issues.

If replication was working previously the service will use cached configuration stored locally but will not respond to any configuration changes until the issue is resolved.

Resolutions

Check the event text to figure out the domain controller which the service was unable to connect to. This event may usually be registered due to one of the following issues:

Network connectivity issues: For more information about troubleshooting network issues, see Knowledge Base article 325487, " How to troubleshoot network connectivity problems on the Microsoft Web site at http://go.microsoft.com/fwlink/?linkid=46059.

Firewall issues: This event may be registered if firewall settings are blocking the ports needed for communication. For more information about which ports to open, see Network Ports Used by Key Microsoft Server Products (http://go.microsoft.com/fwlink/?linkid=57925).

DNS and AD DS issues: This event may be registered because of DNS or AD DS issues. To troubleshoot DNS and AD DS issues, use the following steps:

From a command prompt, type the following command, where <domain.com> is the fully qualified domain name in which the server account exists: nslookup <domain.com>
Verify that the fully qualified domain name (FQDN) of a domain controller is displayed and that the IP address for the domain controller is correct. If anything other than a domain controller with the correct IP address is displayed, troubleshoot DNS name resolution.
Type the following command after logging this error to determine the name of the domain controller the computer logging this event is most likely trying to contact: NLTEST /DSGETDC: <domain.com>

After the issue has been resolved, you should see DFS Replication event 1206 in the System Log in Event Viewer.

Additional

For more information about troubleshooting Active Directory and DNS issues, see http://go.microsoft.com/fwlink

Element properties:

Target

Microsoft.Windows.DfsReplication.Service

Parent Monitor

Microsoft.Windows.DfsReplication.ADPerspectiveAggregateMonitor

Category

StateCollection

Enabled

True

Alert Generate

True

Alert Severity

Error

Alert Priority

High

Alert Auto Resolve

True

Monitor Type

Microsoft.Windows.2SingleEventLog2StateMonitorType

Remotable

True

Accessibility

Public

Alert Message

Service could not contact domain controller to access configuration objects

{0}

RunAs

Default

Source Code:

<UnitMonitor ID="Microsoft.Windows.DfsReplication.DCUnreachableMonitor" Accessibility="Public" Enabled="true" Target="Microsoft.Windows.DfsReplication.Service" ParentMonitorID="Microsoft.Windows.DfsReplication.ADPerspectiveAggregateMonitor" Remotable="true" Priority="Normal" TypeID="Windows!Microsoft.Windows.2SingleEventLog2StateMonitorType" ConfirmDelivery="true">

  <Category>StateCollection</Category>

  <AlertSettings AlertMessage="Microsoft.Windows.DfsReplication.DCUnreachableMonitor_AlertMessageResourceID">

    <AlertOnState>Error</AlertOnState>

    <AutoResolve>true</AutoResolve>

    <AlertPriority>High</AlertPriority>

    <AlertSeverity>Error</AlertSeverity>

    <AlertParameters>

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

    </AlertParameters>

  </AlertSettings>

  <OperationalStates>

    <OperationalState ID="FirstEventRaised" MonitorTypeStateID="FirstEventRaised" HealthState="Error"/>

    <OperationalState ID="SecondEventRaised" MonitorTypeStateID="SecondEventRaised" HealthState="Success"/>

  </OperationalStates>

  <Configuration>

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

    <FirstLogName>DFS Replication</FirstLogName>

    <FirstExpression>

      <And>

        <Expression>

          <SimpleExpression>

            <ValueExpression>

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

            </ValueExpression>

            <Operator>Equal</Operator>

            <ValueExpression>

              <Value Type="UnsignedInteger">1202</Value>

            </ValueExpression>

          </SimpleExpression>

        </Expression>

        <Expression>

          <SimpleExpression>

            <ValueExpression>

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

            </ValueExpression>

            <Operator>Equal</Operator>

            <ValueExpression>

              <Value Type="String">DFSR</Value>

            </ValueExpression>

          </SimpleExpression>

        </Expression>

      </And>

    </FirstExpression>

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

    <SecondLogName>DFS Replication</SecondLogName>

    <SecondExpression>

      <And>

        <Expression>

          <SimpleExpression>

            <ValueExpression>

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

            </ValueExpression>

            <Operator>Equal</Operator>

            <ValueExpression>

              <Value Type="String">DFSR</Value>

            </ValueExpression>

          </SimpleExpression>

        </Expression>

        <Expression>

          <Or>

            <Expression>

              <SimpleExpression>

                <ValueExpression>

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

                </ValueExpression>

                <Operator>Equal</Operator>

                <ValueExpression>

                  <Value Type="UnsignedInteger">1206</Value>

                </ValueExpression>

              </SimpleExpression>

            </Expression>

            <Expression>

              <SimpleExpression>

                <ValueExpression>

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

                </ValueExpression>

                <Operator>Equal</Operator>

                <ValueExpression>

                  <Value Type="UnsignedInteger">1004</Value>

                </ValueExpression>

              </SimpleExpression>

            </Expression>

            <Expression>

              <SimpleExpression>

                <ValueExpression>

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

                </ValueExpression>

                <Operator>Equal</Operator>

                <ValueExpression>

                  <Value Type="UnsignedInteger">1104</Value>

                </ValueExpression>

              </SimpleExpression>

            </Expression>

          </Or>

        </Expression>

      </And>

    </SecondExpression>

  </Configuration>

</UnitMonitor>