3.6.0 MxDB for SQL Server Installation and Administration Guide (5697-7088, December 2007)

Chapter 7: Troubleshooting 97

NOTE: If the nslookup fails, make sure a PTR record is created in DNS for

the virtual IP. Nslookup may require you to “set type=PTR” and

lookup the in-addr reverse form of the IP. For example:

C:\>nslookup

Default Server: qadc1.ad1.polyserve.com

Address: 99.11.0.31

> set type=PTR

> 181.13.11.99.in-addr.arpa

Server: qadc1.ad1.polyserve.com

Address: 99.11.0.31

181.13.11.99.in-addr.arpa name =

vqar13s11.ad1.polyserve.com

> 99.11.13.181

Server: qadc1.ad1.polyserve.com

Address: 99.11.0.31

181.13.11.99.in-addr.arpa name =

vqar13s11.ad1.polyserve.com

When a SQL client uses integrated security (SSPI) to connect to a SQL

Server, the SQL driver authenticates the client via the strong network

authentication, Kerberos first. If Kerberos is not available, NTLM

authentication is then used to authenticate the client. Kerberos

authentication is used only if the following prerequisites are met:

• Both the client and server computers are running Windows 2000 SP3

or higher.

• Both the client and server computers are part of the same domain or

trusted domains.

• The SQL Server service SPN is registered with Active Directory.

• The SQL Server instance is listening on TCP/IP.

• The SQL client is connecting over TCP/IP.

Kerberos uses a domain unique identifier, “Service Principal Name”

(SPN), to identify a resource within a network. An SPN for SQL Server is

composed of three components:

• ServiceClass: the class of service. MSSQLSvc is for SQL Server.