Telephony equipment errors when the Internet telephony system runs on a Windows Server 2012 R2-based DNS server

Applies to: Windows Server 2012 R2 DatacenterWindows Server 2012 R2 StandardWindows Server 2012 R2 Essentials


Consider the following scenario:

  • You have a DNS server that is running Windows Server 2008 or later versions.
  • The DNS server provides DNS services for the Internet telephony system.
  • The Internet telephony system uses the Name Authority Pointer (NAPTR) records to locate Session Initiation Protocol (SIP) services for telephones.
  • The DNS server compresses the DNS NAPTR records before the records are sent on the wire.
  • The telephony equipment or the other downstream clients decompress the NAPTR records.
In this scenario, the telephony equipment or the other downstream clients receive errors.

How to obtain this update or hotfix

To resolve this issue, we have released update rollup and a hotfix for Windows Server 2012 R2.

Before you install this hotfix, check the prerequisite of the hotfix.

The update rollup fixes many other issues in addition to the issue that the hotfix fixes. We recommend that you use the update rollup. The update rollup is larger than the hotfix. Therefore, the update rollup takes longer to download.

Note There is no hotfix for Windows Server 2008, Windows Server 2008 R2, or Windows Server 2012. We recommend that you upgrade the server to Windows Server 2012 R2 to apply this hotfix.

Update for Windows Server 2012 R2

The following update rollup is available.

For Windows Server 2012 R2

Get update rollup 2995388

Hotfix for Windows Server 2012 R2

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem.

If the hotfix is available for download, there is a "Hotfix Download Available" section at the top of this Knowledge Base article. If this section does not appear, submit a request to Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft website: Note The "Hotfix Download Available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.


To apply this hotfix, you must first install update 2919355 in Windows 8.1 or Windows Server 2012 R2. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

2919355 Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 Update April, 2014

Registry information

To use the hotfix in this package, you do not have to make any changes to the registry.

Restart requirement

You may have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

More Information

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates.


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.