Windows Server: DNS Resolution is Delayed or Fails in Active Directory Domain due to Improper Configuration of Forwarders

Summary: If forwarders are improperly configured on DNS servers in an Active Directory domain, name resolution may fail or take longer than expected. This typically affects resolution of external DNS names only. ...

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Symptoms

External DNS name resolution fails outright or takes longer than expected. Internal name resolution may function without issues, as forwarders are not used for internal resolution.

Cause

Improper configuration of forwarders on DNS servers in a domain may cause delays or failures of external DNS resolution. Specifically, DNS servers within a domain, which are almost always domain controllers (DCs) for that domain, should not be configured to forward to one another. Only DNS servers outside the domain should be used as forwarders.

Good candidates for forwarders include the following:

  • Well-known public DNS servers with easy-to-remember IP addresses (1.1.1.1, 8.8.8.8, 9.9.9.9, and others)
  • DNS servers provided by your Internet Service Provider (ISP)

Other public DNS servers may provide good responses as well.

It is also possible to use root hints instead of forwarders for external name resolution. This article is only applicable if forwarders are in use.

Resolution

To address the issue, perform the following steps:

  1. On a DNS server, launch the DNS Manager console.
  2. In the left pane of the console, right-click the server and select Properties. It may be necessary to left-click the server before it can be right-clicked.
  3. Click the Forwarders tab and review the list of forwarders.
  4. If any internal DNS servers are in the list of forwarders, click the Edit button and delete every internal server from the list. Supply any additional forwarders that are needed.
  5. Click OK to close the Edit Forwarders window, then again to close the Properties window.
  6. Right-click the server and select Clear Cache. This is necessary to accurately evaluate the response time of external name resolution.

Repeat the above steps on all DNS servers in the domain. Forwarders are configured on a per-server basis and are not replicated between servers.

After performing these steps, use the nslookup command to test name resolution and confirm the response time.

Additional Information

With a few exceptions, DNS servers within a domain all have the same records in their zones if DNS is properly configured. This is true whether standard or Active Directory-integrated zones are used, assuming zone transfers or Active Directory replication are functional. Therefore, if one DNS server is unable to answer a query, others in the domain are also unable to do so. Forwarding queries between these servers only slows down the name-resolution process.

Affected Products

Microsoft Windows Server 2016, Microsoft Windows Server 2019, Microsoft Windows Server 2022

Products

PowerEdge M640, PowerEdge M640 (for PE VRTX), PowerEdge MX740C, PowerEdge MX750c, PowerEdge MX760c, PowerEdge MX840C, PowerEdge R240, PowerEdge R250, PowerEdge R260, PowerEdge R340, PowerEdge R350, PowerEdge R360, PowerEdge R440, PowerEdge R450 , PowerEdge R540, PowerEdge R550, PowerEdge R640, PowerEdge R6415, PowerEdge R650, PowerEdge R650xs, PowerEdge R6515, PowerEdge R6525, PowerEdge R660, PowerEdge R660xs, PowerEdge R6615, PowerEdge R6625, PowerEdge R740, PowerEdge R740XD, PowerEdge R740XD2, PowerEdge R7415, PowerEdge R7425, PowerEdge R750, PowerEdge R750XA, PowerEdge R750xs, PowerEdge R7515, PowerEdge R7525, PowerEdge R760, PowerEdge R760XA, PowerEdge R760xd2, PowerEdge R760xs, PowerEdge R7615, PowerEdge R7625, PowerEdge R840, PowerEdge R860, PowerEdge R940, PowerEdge R940xa, PowerEdge R960, PowerEdge T140, PowerEdge T150, PowerEdge T160, PowerEdge T340, PowerEdge T350, PowerEdge T360, PowerEdge T440, PowerEdge T550, PowerEdge T560, PowerEdge T640 ...
Article Properties
Article Number: 000212612
Article Type: Solution
Last Modified: 10 Dec 2024
Version:  5
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