MSExchange ADAccess 2120

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This article provides an explanation and possible resolutions for a specific Exchange event. If you don't find what you’re looking for here, try searching Exchange 2010 Help.

Details

Product Name

Exchange

Product Version

14.0

Event ID

2120

Category

Topology

Symbolic Name

DSC_EVENT_DNS_TIMEOUT

Message Text

Process %1 (PID=%2). Error ERROR_TIMEOUT (0x%3) occurred when DNS was queried for the service location (SRV) resource record used to locate a domain controller for domain %4%n The query was for the SRV record for %5%n. The DNS servers used by this computer for name resolution are not responding. This computer is configured to use DNS servers with the following IP addresses:%n%6%n. Verify that this computer is connected to the network, that these are the correct DNS server IP addresses, and that at least one of the DNS servers is running.%n For information about correcting this problem, %7%8

Explanation

This Warning event indicates that DNS servers for the specified domain are not responding. The domain controllers from the specified domain will not be used by DSAccess. As long as there is sufficient capacity in usable domain controllers in other domains, it will not cause mail flow interruption. However, we recommend that you investigate the issue and fix it.

If the event contains the name of the local domain, topology discovery cannot be completed, and this will cause mail flow interruption.

This event may be logged when the following conditions occur:

  • The DNS servers did not respond because there is a connectivity problem.

  • There is no connectivity problem and the DNS servers are running. However, this computer could be using DHCP to obtain IP addresses for its DNS servers and the DHCP server could be providing incorrect IP addresses.

User Action

If this event is rarely seen, it can safely be ignored. To resolve this event, do one or more of the following:

  • If this Warning event is logged at specific times or if any other pattern is detected, do the following:

    • Verify that the IP addresses of the DNS servers that are used by this computer are correct.

    • Determine whether DNS servers are running. For more information about how to troubleshoot DNS issues, see DNS Troubleshooting.

    • Determine whether this computer uses DHCP to obtain its DNS server IP addresses by typing ipconfig /all at the command prompt. Then, if the DHCP Enabled setting is set to Yes, this computer uses DHCP to obtain DNS server addresses. Contact the network administrator to verify that the DHCP server is running and providing correct DNS server IP addresses.

  • Use the Ping or PathPing command-line tools to test basic connectivity. Use Ping to isolate network hardware problems and incompatible configurations. Use PathPing to detect packet loss over multiple-hop trips. For more information, see Microsoft Knowledge Base article 325487, Advanced network adapter troubleshooting for Windows workstations.

  • Run the Dcdiag command-line tool to test domain controller health. To do this, run dcdiag /s:[Domain Controller Name] at a command prompt on the Exchange server. Use the output of Dcdiag to discover the root cause of any failures or warnings that it reports. For more information, see Dcdiag Overview at the Windows Server TechCenter.

For More Information

If you are not already doing so, consider running the Exchange tools, which have been created to help you analyze and troubleshoot your Exchange environment. These tools can help make sure that your configuration aligns with Microsoft best practices. They can also help you identify and resolve performance issues and improve mail flow. To run these tools, go to the Toolbox node of the Exchange Management Console. To learn more about these tools, see Managing Tools in the Toolbox.