ISDN line makes connection to remote WAN sites every 15 minutes

If you have two remote sites in your domain that are connected by an Integrated Services Digital Network (ISDN) line, and the ISDN line is scheduled to make a connection one time per hour, the line may instead make a connection every 15 minutes.

This issue is caused by a DsGetDcName function call. This function returns the name of the primary domain controller (PDC) in a specified domain every 15 minutes. This may generate a Lightweight Directory Access Protocol (LDAP) query to the PDC of the domain. If the PDC is not found on the local site, a connection to a remote site is automatically opened.

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 Web site: 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.
The Global version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

If you want to use event ID 2080 to diagnose Exchange DSAccess issues and to confirm whether the domain controller is a primary domain controller for its domain, you must add the MinUserDC registry value. For more information, click the following article numbers to view the articles in the Microsoft Knowledge Base:

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