Error when you attempt to create a DFS namespace: The namespace cannot be queried. The RPC server is unavailable

This article provides a solution to an error that occurs when you create a DFS namespace.

Original product version:   Windows Server 2012 R2
Original KB number:   2021914


You may receive the following error when attempting to create a DFS namespace on a Windows Server 2008 computer:

The namespace cannot be queried. The RPC server is unavailable.

This issue is typically seen in an environment using a third-party DNS server.


This error can occur when no DomainDNSName records are registered for the domain. These records are updated by the Netlogon service on domain controllers. These are the same as parent A records in domain's forward lookup zone.

The following documentation indicates these records are not a requirement and are only used for DNS clients that do not understand SRV records:
How DNS Support for Active Directory Works.


Enables a non-SRV-aware client to locate any domain controller in the domain by looking up an A record. A name in this form is returned to the LDAP client through an LDAP referral. A non-SRV-aware client looks up the name; an SRV-aware client looks up the appropriate SRV resource record.

In a network trace, you will see a DNS lookup for the DomainDNSname A record and the DNS server will respond with the SOA record if these A records do not exist.

DNS lookup query:

Dns: QueryId = 0x887C, QUERY (Standard query), Query for of type Host Addr on class Internet
QRecord: of type Host Addr on class Internet

Response with the SOA record:

Dns: QueryId = 0x887C, QUERY (Standard query), Response - Success
QRecord: of type Host Addr on class Internet
AuthorityRecord: of type SOA on class Internet: PrimaryNameServer:, AuthoritativeMailbox:


Update the A records on the DNS server, or create a HOSTS file on the Windows Server 2008 computer that includes the fully qualified name and the IP addresses of the domain controller.

Sample HOSTS file: