为什么对SQL Server Express Edition 2014的远程访问失败？

Question

I've just installed SQL Server 2014 Express edition on my W7 work station. Please help me to connect to the new instance from my old kind Windows XP. Command line sessions below provide details (remote access is allowed). Google search did not help much.

On computer that hosts the new instance (10.0.0.100, "server" workstation) both instances are accessible:

C:\1>hostname
FDE-HQ-WK4
C:\1>sqlcmd -Sfde-hq-wk4\sql2014 -Usa -Pdbasql -Q"select @@version select @@servername"
----------------------------------------------------------------------------------------

Microsoft SQL Server 2014 - 12.0.2000.8 (Intel X86)
        Feb 20 2014 19:20:46
        Copyright (c) Microsoft Corporation
        Express Edition on Windows NT 6.1 <X86> (Build 7601: Service Pack 1)
----------------------------------------------------------------------------------------
FDE-HQ-WK4\SQL2014

C:\1>sqlcmd -Sfde-hq-wk4 -Usa -Pdbasql -Q"select @@version select @@servername"
----------------------------------------------------------------------------------------
Microsoft SQL Server 2008 (SP1) - 10.0.2531.0 (Intel X86)
        Mar 29 2009 10:27:29
        Copyright (c) 1988-2008 Microsoft Corporation
        Express Edition on Windows NT 6.1 <X86> (Build 7601: Service Pack 1)
----------------------------------------------------------------------------------------
FDE-HQ-WK4\SQLEXPRESS

The next session is on a computer (10.0.0.113 "client" workstation) that physically shares my desk with the previous one, old instance works fine but connection to the new one fails:

d:\1>sqlcmd -Sfde-hq-wk4 -Usa -Pdbasql -Q"select @@version select @@servername"
-------------------------------------------------------------------------------------------------
Microsoft SQL Server 2008 (SP1) - 10.0.2531.0 (Intel X86)
        Mar 29 2009 10:27:29
        Copyright (c) 1988-2008 Microsoft Corporation
        Express Edition on Windows NT 6.1 <X86> (Build 7601: Service Pack 1)
-------------------------------------------------------------------------------------------------
FDE-HQ-WK4\SQLEXPRESS

d:\1>sqlcmd -Sfde-hq-wk4\sql2014 -Usa -Pdbasql -Q"select @@version select @@servername"
HResult 0xFFFFFFFF, Level 16, State 1
SQL Network Interfaces: Error Locating Server/Instance Specified [xFFFFFFFF].
Sqlcmd: Error: Microsoft SQL Native Client : An error has occurred while establishing a connectio
the default settings SQL Server does not allow remote connections..
Sqlcmd: Error: Microsoft SQL Native Client : Login timeout expired.

d:\1>

Answer 1

When connecting to a named instance using the TCP sockets library, the client will use two methods to determine what port to connect to.

1. It will connect to TCP 1433 to talk to the default instance of SQL Server. One of the duties of the default instance is to keep track of all named instances and the ports they are currently listening on.
2. It will connect to UDP 1434 to talk to the SQL Browser service. One of its duties of SQL Browser is to keep track of all named instances and the ports they are currently listening on.

If the client cannot connect to either of these then the connection attempt will fail. In this case, you are required to specify the port number in the connection. In your case. sqlcmd -S fde-hq-wk4\\sql2014 fails because neither the default instance nor SQL Browser is running.

Your answer in fact suggests you are running a named instance, fde-hq-wk4\\sql2014, on the default port. This named instance does not keep track of instances and port allocations. Thus, your "unfortunate behaviour" sounds like a result of your unfortunate choice of installation.

As to why the connection works when running locally, in that case it is probably using the SHared Memory network library.

Short answer - if you don't want to run SQL Browser (it sends a fair amount of broadcast traffic, so most people leave it disabled) then hard code the port numbers in your connection strings.

Answer 2

I agree with Greenstone Walker. By default SQL Express do not enable the TCP/IP protocol. You can login to SQL server configuration manager , select the protocols under your installed instance and check if TCP/IP is enabled. If not enabled, enable it and check the settings. You will need to restart the SQL services to apply the changes.

Answer 3

The following does work:

C:\1>sqlcmd -Sfde-hq-wk4\sql2014 -Upacrat -Ppacratdba -Q "select @@version selec
t @@servername"
Sqlcmd: Error: Microsoft SQL Server Native Client 11.0 : SQL Server Network Inte
...
 SQL Server Books Online..

C:\1>sqlcmd -Sfde-hq-wk4\sql2014,1433 -Upacrat -Ppacratdba -Q "select @@version
select @@servername"
------------------------------------------------------------
Microsoft SQL Server 2008 (SP1) - 10.0.2531.0 (Intel X86)
        Mar 29 2009 10:27:29
        Copyright (c) 1988-2008 Microsoft Corporation
        Express Edition on Windows NT 6.1 <X86> (Build 7601: Service Pack 1)
------------------------------------------------
FDE-HQ-WK4\SQLEXPRESS

C:\\1>

Thanks everybody, and please keep in mind this unfortunate Express Edition behavior.