Windows 2000 DNS may not evenly distribute round-robin name resolution if you enable both netmask ordering and round-robin host name resolution (826454)

SYMPTOMS

If you enable both round-robin host name resolution and netmask ordering for Microsoft Windows 2000 DNS, DNS may not evenly distribute round-robin name resolution.

For example, consider the following scenario:

Windows 2000 DNS is configured with the following records:

myhost.mydomain.com A 192.168.0.1
myhost.mydomain.com A 192.168.0.2
myhost.mydomain.com A 10.0.0.1
myhost.mydomain.com A 10.0.0.2
myhost.mydomain.com A 10.0.0.3

When a client with an IP address of 192.168.0.10 queries myhost.mydomain.com against DNS, DNS returns the following addresses:

If you have not applied hotfix 818451, the first IP address is always 192.168.0.1.
If you have applied hotfix 818451, the first IP address is 192.168.0.1 for 80 percent of the queries.
If you have applied hotfix 818451, the first IP address is 192.168.0.2 for 20 percent of the queries.

The client expects that the first IP address that DNS returns will be between 192.168.0.1 and 192.168.0.2 because both round-robin host name resolution and netmask ordering are enabled in Windows 2000 DNS.

RESOLUTION

Hotfix information

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

Prerequisites

No prerequisites are required.

Restart requirement

You do not have to restart your computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later) 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.

   Date         Time   Version            Size    File name
   --------------------------------------------------------------
   07-Nov-2003  18:14  5.0.2195.6872     327,440  Dns.exe

MORE INFORMATION

For additional information, click the following article numbers to view the articles in the Microsoft Knowledge Base:

816915 New file naming schema for Microsoft Windows software update packages

824684 Description of the standard terminology that is used to describe Microsoft software updates