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Original KB number: 267855
Applies to: Supported versions of Windows Server
Symptoms
Domain Name System (DNS) registrations of SRV and domain controller (DC) locator A records (registered by Netlogon) and NS records (added by the authoritative DNS servers) in an Active Directory-integrated DNS zone for some DCs might not work in a domain that contains a large number of DCs.
For Windows Server 2022 and earlier versions, you can have about 1,200 DCs and DNS servers register all DNS records relevant to operating the DNS zones and domains. For Windows Server 2025, you can enable an optional feature that allows about 3,200 DCs to register their DNS records. See the References section for details.
One or more of the following error messages might be logged in the Event log:
Event Type: Error
Event Source: DNS
Event Category: None
Event ID: 4011
Description: The DNS server was unable to add or write an update of domain name xyz in zone xyz.example.com to the Active Directory. Check that the Active Directory is functioning properly and add or update this domain name using the DNS console. The event data contains the error.
Data: 0000: 2a 23 00 00 *#..
Event Type: Error
Event Source: DNS
Event Category: None
Event ID: 4015
Description: The DNS server has encountered a critical error from the Active Directory. Check that the Active Directory is functioning properly. The event data contains the error.
Data: 0000: 0b 00 00 00 ....
Event Type: Warning
Event Source: NTDS Replication
Event Category: Replication
Event ID: 1093
Description: The directory replication agent (DRA) could not apply changes to object DC=@,DC=xyz.example.com,CN=MicrosoftDNS,CN=System,DC=xyz,DC=example, DC=com (GUID <GUID>) because the incoming changes cause the object to exceed the database's record size limit. The incoming change to attribute 9017e (dnsRecord) will be backed out in an attempt to make the update fit. In addition to the change to the attribute not being applied locally, the current value of the attribute on this system will be sent out to all other systems to make that the definitive version. This has the effect of nullifying the change to the rest of the enterprise.
The reversal may be recognized as follows:
Version:
5474
Time of change:
<DateTime>
Update sequence number:
<USN>
Event Type: Information
Event Source: NTDS Replication
Event Category: Replication
Event ID: 1101
Description: The directory replication agent (DRA) was able to successfully apply the changes to object DC=@,DC=xyz.example.com,CN=MicrosoftDNS,CN=System, DC=xyz,DC=example,DC=com (GUID <GUID>) after backing out one or more of the attribute changes. Preceding messages will indicate which attributes were reversed. Please note that this will have the effect of nullifying the change where it was made, causing the original update not to take effect. The originator should be notified that their change was not accepted by the system.
Cause
In an Active Directory (AD)-integrated DNS zone, DNS names are represented by dnsNode objects, and DNS records are stored as values in the multi-valued dnsRecord attribute on dnsNode objects, causing the error messages listed earlier in this article to occur.
This problem occurs because Active Directory has a limitation of approximately 1,200 values that can be associated with a single object in Windows Server 2022 and earlier versions. For Windows Server 2025, this limit can be lifted to about 3,200 values.
Resolution
You can use the following methods to resolve this issue.
Experiencing the problem with the NS records of a zone
Method 1
If your DCs are also DNS servers, they all host the AD-integrated zones, and all would add themselves to the NS record for the zone by default. If you exceed the limit for non-linked attributes, updates to the DNS record AD object will fail.
If you want to reduce the list of DNS servers that can add NS records corresponding to themselves to a specified zone, choose a subset of DNS servers and then run Dnscmd.exe with the /AllowNSRecordsAutoCreation switch. Consider having DCs in the list that are well-connected to the network and well-monitored. This can be a set of DCs running in your central datacenters.
To set a list of TCP/IP addresses of DNS servers that have permission to automatically create NS records for a zone, use the
/AllowNSRecordsAutoCreation IPListcommand. For example:Dnscmd NS1 /config zonename.com /AllowNSRecordsAutoCreation 10.1.1.1 10.5.4.2To clear the list of TCP/IP addresses of DNS servers that have permission to automatically create NS records for a zone and return the zone to the default state when every primary DNS server automatically adds to a zone an NS record corresponding to it, use the
/AllowNSRecordsAutoCreationcommand. For example:Dnscmd NS1 /config zonename.com /AllowNSRecordsAutoCreationTo query the list of TCP/IP addresses of DNS servers that have permission to automatically create NS records for a zone, use the
/AllowNSRecordsAutoCreationcommand. For example:Dnscmd NS1 /zoneinfo zonename.com /AllowNSRecordsAutoCreation
Note
Run this command on only one DNS server. Active Directory replication propagates the changes to all DNS servers that are running on DCs in the same domain.
In an environment in which the majority of the DNS DCs for a domain are located in branch offices and a few are located in a central location, you might want to use the Dnscmd command described earlier in this article to set the IPList to include only the centrally located DNS DCs. By doing so, only the centrally located DNS DCs add their respective NS records to the Active Directory domain zone.
Method 2
Important
This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information, see How to back up and restore the registry in Windows.
Similar to method 1, pick a number of DCs you want to have present with an NS record for the zones they host. For the DNS servers you don't want to add NS records corresponding to themselves to any AD-integrated DNS zone, use Registry Editor (Regedt32.exe) to configure the following registry value on each affected DNS server:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DNS\Parameters
Registry value: DisableNSRecordsAutoCreation
Data type: REG_DWORD
Data range: 0x0 | 0x1
Default value: 0x0
This value affects all AD-integrated DNS zones. The values have the following meanings:
| Value | Meaning |
|---|---|
| 0 | DNS server automatically creates NS records for all Active Directory-integrated DNS zones unless any zone, that is hosted by the server, contains the AllowNSRecordsAutoCreation attribute (described earlier in this article) that doesn't include the server. In this situation, the server uses the AllowNSRecordsAutoCreation configuration. |
| 1 | DNS server doesn't automatically create NS records for all Active Directory-integrated DNS zones, regardless of the AllowNSRecordsAutoCreation configuration in the Active Directory-integrated DNS zones. |
Note
To apply the changes to this value, you must restart the DNS Server service.
Experiencing the problem with the SRV and A records of a zone owned by DCs
Important
This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information, see How to back up and restore the registry in Windows.
Netlogon manages the registration of a DC's DNS record. To prevent a DC from attempting dynamic updates of certain DNS records that by default are dynamically updated by Netlogon, use Regedt32.exe to configure the following registry value:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Netlogon\Parameters
Registry value: DnsAvoidRegisterRecords
Data type: REG_MULTI_SZ
In this value, specify the list of mnemonics corresponding to the DNS records that shouldn't be registered by this DC.
Note
Set the value to the list of the enter-delimited mnemonics that are specified in the following table.
The list of mnemonics includes:
| Mnemonic | Type | DNS Record |
|---|---|---|
| LdapIpAddress | A | <DnsDomainName> |
| Ldap | SRV | _ldap._tcp.<DnsDomainName> |
| LdapAtSite | SRV | _ldap._tcp.<SiteName>._sites.<DnsDomainName> |
| Pdc | SRV | _ldap._tcp.pdc._msdcs.<DnsDomainName> |
| Gc | SRV | _ldap._tcp.gc._msdcs.<DnsForestName> |
| GcAtSite | SRV | _ldap._tcp.<SiteName>._sites.gc._msdcs.<DnsForestName> |
| DcByGuid | SRV | _ldap._tcp.<DomainGuid>.domains._msdcs.<DnsForestName> |
| GcIpAddress | A | gc._msdcs.<DnsForestName> |
| DsaCname | CNAME | <DsaGuid>._msdcs.<DnsForestName> |
| Kdc | SRV | _kerberos._tcp.dc._msdcs.<DnsDomainName> |
| KdcAtSite | SRV | _kerberos._tcp.<SiteName>._sites.dc._msdcs.<DnsDomainName> |
| Dc | SRV | _ldap._tcp.dc._msdcs.<DnsDomainName> |
| DcAtSite | SRV | _ldap._tcp.<SiteName>._sites.dc._msdcs.<DnsDomainName> |
| Rfc1510Kdc | SRV | _kerberos._tcp.<DnsDomainName> |
| Rfc1510KdcAtSite | SRV | _kerberos._tcp.<SiteName>._sites.<DnsDomainName> |
| GenericGc | SRV | _gc._tcp.<DnsForestName> |
| GenericGcAtSite | SRV | _gc._tcp.<SiteName>._sites.<DnsForestName> |
| Rfc1510UdpKdc | SRV | _kerberos._udp.<DnsDomainName> |
| Rfc1510Kpwd | SRV | _kpasswd._tcp.<DnsDomainName> |
| Rfc1510UdpKpwd | SRV | _kpasswd._udp.<DnsDomainName> |
Note
It isn't necessary to restart the Netlogon service. If the DnsAvoidRegisterRecords registry value is created or modified while the Netlogon service is stopped or within the first 15 minutes after Netlogon is started, appropriate DNS updates take place with a short delay (however, the delay is no later than 15 minutes after Netlogon starts).
You can also set the list of DNS records to suppress using a Group Policy:
GPS: Specify DC Locator DNS records not registered by the DCs
DNS registrations of A records performed by Netlogon can be also be modified by using the RegisterDnsARecords registry value. For more information, see How to enable or disable DNS updates in Windows.
Be aware that both the DnsAvoidRegisterRecords and the RegisterDnsARecords registry values need to allow registering the host (A) record:
- RegisterDnsARecords = 0x1
If you list LdapIpAddress and GcIpAddress in theDnsAvoidRegisterRecordsregistry value settings, A records aren't registered. - RegisterDnsARecords = 0x0
No matter whether you list LdapIpAddress and GcIpAddress in theDnsAvoidRegisterRecordsregistry value settings, A records aren't registered.
To prevent the problem described earlier in this article from occurring in an environment in which a set of DCs and/or global catalog (GC) servers are located in a central location and a large number of the DCs and/or GC servers are located in branch offices, the administrator can disable registration of some of the DNS records by Netlogon on the DCs/GCs in the branch offices. In this situation, the list of mnemonics that should not be registered includes:
DC-specific records:
| Mnemonic | Type | DNS Record |
|---|---|---|
| LdapIpAddress | A | <DnsDomainName> |
| Ldap | SRV | _ldap._tcp.<DnsDomainName> |
| DcByGuid | SRV | _ldap._tcp.<DomainGuid>.domains._msdcs.<DnsForestName> |
| Kdc | SRV | _kerberos._tcp.dc._msdcs.<DnsDomainName> |
| Dc | SRV | _ldap._tcp.dc._msdcs.<DnsDomainName> |
| Rfc1510Kdc | SRV | _kerberos._tcp.<DnsDomainName> |
| Rfc1510UdpKdc | SRV | _kerberos._udp.<DnsDomainName> |
| Rfc1510Kpwd | SRV | _kpasswd._tcp.<DnsDomainName> |
| Rfc1510UdpKpwd | SRV | _kpasswd._udp.<DnsDomainName> |
GC-specific records:
| Mnemonic | Type | DNS Record |
|---|---|---|
| Gc | SRV | _ldap._tcp.gc._msdcs.<DnsForestName> |
| GcIpAddress | A | gc._msdcs.<DnsForestName> |
| GenericGc | SRV | _gc._tcp.<DnsForestName> |
Note
These lists do not include the site-specific records. Therefore, DCs and GC servers in branch offices are located by site-specific records that are usually used by a DC locator. If a program searches for a DC/GC by using generic (non-site-specific) records such as any of the records in the lists that are listed earlier in this article, it finds a DC/GC in the central location.
Read-only DCs default to registering DNS records specific to their site.
An administrator might also choose to limit the number of the DC locator records, such as SRV and A records registered by Netlogon for the same generic DNS name (_ldap._tcp.dc._msdcs.<DomainName>), even in a scenario with fewer DCs than the non-linked attribute value limit in the same domain, to reduce the size of DNS responses to queries for such records.
You can create this setting in a Group Policy linked to the DCs OU, put all branch DCs into an "AD Branch DCs" group, and set the Group Policy to apply only to members of the "AD Branch DCs" group.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
More information
Every DNS server that is authoritative for an Active Directory-integrated DNS zone adds an NS record. By default, every DC in a domain registers an SRV record for a set of non-site-specific names such as "_ldap._tcp.<domain_name>" and A record(s) that map(s) the Active Directory DNS domain name to the TCP/IP address(es) of the DC. When a DNS server tries to write a record with many values for the same shared name, Local Security Authority Subsystem Service (LSASS) runs at 100% CPU usage for approximately 10 seconds and the registration doesn't succeed. Netlogon retries this registration every hour; the 100% CPU usage spike reappears at least once an hour, and the attempted registrations don't succeed.