DOCUMENT:Q255880 11-JUN-2002 [winnt] TITLE :Event ID 1540 When Attempting to Add Reverse Lookup Zones PRODUCT :Microsoft Windows NT PROD/VER:winnt:4.0,4.0 SP1,4.0 SP2,4.0 SP3,4.0 SP4,4.0 SP5,4.0 SP6,4.0 SP6a OPER/SYS: KEYWORDS:kberrmsg kbnetwork kbtool kbui ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server versions 4.0, 4.0 SP1, 4.0 SP2, 4.0 SP3, 4.0 SP4, 4.0 SP5, 4.0 SP6, 4.0 SP6a ------------------------------------------------------------------------------- IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base: Q256986 Description of the Microsoft Windows Registry SYMPTOMS ======== In DNS Manager, when you try to manually add any of the following reverse lookup zones 0.in-addr.arpa. 255.in-addr-arpa. 127.in-addr.arpa. you may receive the following error message: The new zone couldn't be created because there is already a zone by this name. Verify that the zone name was entered correctly or choose a new zone name. The process is terminated by DNS and the zone is not created. In addition, the following entry is displayed in the system log of Event Viewer: Event ID: 1540 Source: DNS Type: Error Description: DNS Server unable to create domain node. CAUSE ===== This behavior can occur for one of the following reasons: - The Show Automatically Created Zones check box (click Options, and then click Preferences) is cleared (by default) or the ShowAutoCreatedZones registry value is set to 0. NOTE: When a DNS server is created, these three reverse lookup zones are automatically created (in memory only and not stored in a zone file) by default. However, in DNS Manager the Show Automatically Created Zones option is disabled by default, and the automatically created zones are therefore not displayed. This may lead you to believe that those zones are not created. - When the DisableAutoReverseZones registry value is accidentally set to 1 or a non-zero value. RESOLUTION ========== To resolve this issue, use the appropriate method. Method 1 -------- 1. In DNS Manager, click to select the Show Automatically Created Zones check box or set the ShowAutoCreatedZones registry value to a non-zero value. 2. In DNS Manager, right-click the server name, and then click Update Server Data Files. 3. Right-click the server name again, and then click Refresh. Method 2 -------- WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk. If the DisableAutoReverseZones value exists, make sure it is set to 0. MORE INFORMATION ================ The ShowAutoCreatedZones value is located in the following registry key: HKEY_LOCAL_MACHINE\Software\Microsoft\DNSAdministrator\Parameters Value: ShowAutoCreatedZones Type: Reg_DWORD (Boolean) Default: 1 (SP5 or earlier), 0 (SP6 and SP6a) Value Range: 0 (False) or 1 (True) Function: Determines if the server shows the automatically created zones, including the standard reverse lookup zones The DisableAutoReverseZones value is located in the following registry key: HKEY_LOCAL_MACHINE\System\Ccs\Services\Dns\Parameters Value: DisableAutoReverseZones Added in: Windows NT 4.0 Type: Reg_DWORD (Boolean) Default: NoKey (Create automatic reverse lookup zones) Value Range: 0 (False) or 1 (True) Function: Determines if the server automatically creates standard reverse lookup zones NOTE: If the DisableAutoReverseZones value does not exist or if it is set to 0, the DNS server automatically creates these zones with the correct entries (except for a PTR for 127.0.0.1 to localhost). If the DisableAutoReverseZones value is set to non-zero, the server does not create these zones. Every DNS server should be authoritative for three reverse lookup zones according to RFC: 0.in-addr.arpa. 127.in-addr.arpa. 255.in-addr.arpa. These zones are used for localhost lookups/queries such as 0.0.0.0, 127.0.0.1 (loopback), and 255.255.255.255 (broadcast). By being authoritative for the zones corresponding to these queries, the DNS server avoids unnecessary recursions to the root servers on these queries, so they should always exist on the DNS server. Therefore, the DisableAutoReverseZones value should normally not be enabled because if the zones do not exist, lookup to any of the zones is sent to a root server. If you need to modify the localhost (127.0.0.x) reverse lookup zone, you must manually create it. The correct name for this zone is 0.0.127.in-addr.arpa. Additional query words: domain node ====================================================================== Keywords : kberrmsg kbnetwork kbtool kbui Technology : kbWinNTsearch kbWinNT400search kbWinNTSsearch kbWinNTS400sp6 kbWinNTS400sp5 kbWinNTS400sp4 kbWinNTS400sp3 kbWinNTS400sp2 kbWinNTS400sp1 kbWinNTS400search kbWinNTS400 Version : winnt:4.0,4.0 SP1,4.0 SP2,4.0 SP3,4.0 SP4,4.0 SP5,4.0 SP6,4.0 SP6a Issue type : kbprb ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 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