SQL Server 2005 Remote Connectivity Issue TroubleShoot

With shipping SQL Server 2005, we heard from customer feedback about suffering make successful remote connection against SQL 2k5, plus, if running SQL Server on XP/WIN2K3/VISTA behind firewall, such problem occurs more frequently and harder for customer to get clue of behind reason.

I. Background of remote connectivity issue.

The reason we saw the issue comes out w/ SQL 2k5 instead of SQL 2k is because two breaking change in SQL 2k5 compared to SQL 2000.

1) Network Protocols Off by Default: In order to make system secure, we limit connectivity when a user install SQL 2k5, thereby reducing surface area for attack. By default, SQL server (SQLEXPR, SQLDEV and EVAL SKUs), on installation will listen only on Shared memory and local-only Named Pipe. TCP and remote Named Pipe will be off-by-default. VIA will also be off-by-default; SQL server (SQLENT, STANDARD and Workgroup SKUs), on installation will listen only on Shared memory, local-only Named Pipe and TCP. Remote Named Pipe will be off-by-default. VIA will also be off-by-default.

Therefore, when you mae remote connection, you should make sure at least either Named Pipe or TCP are enabled in your remote SQL instance.

2) SQL Browser service: which is a replacement of SSRP system in SQL Server 2000, run as a Windows Service on installation of SQL 2k5. Upon startup, SQL Server Browser starts and claims UDP port 1434. When SQL Server 2000 and SQL Server 2005 clients request SQL Server resources, the client network library sends a UDP message to the server using port 1434. SQL Server Browser responds with the TCP/IP port or named pipe of the requested instance.

Therefore, you need to make sure SQL Browser is enabled and started when remote client ask for which tcp port or pipe name SQL Server is listening on. If your remote SQL Instance is a default instance, you do not necessary enable sql browser since client would always try default TCP port 1433 and pipe name \<remoterserver>pipesqlquery. But, if you have SQL 2k5 named instance installed or SQL 2000 and SQL 2k5 side by side installed, you must enable and start sqlbrowser.

II. Problem list:

By understanding background 1) and 2), I belive you can imagine issues you may face when make remote connection against SQL 2k5:

1) Fail to connect over TCP/IP or Named Pipe if  the request protocol was not enabled.

2) Fail to connect over TCP/IP or Named Pipe if Firewall enabled on the remote server and tcp port or "File and Printer Sharing"  is not added to the Firewall exception list.

3) Fail to connect to remote sql named instance if SQL Browser was not enabled or UDP port 1434 that browser listening on is added to the Firewall exception list.

III. Troubleshooting Tips:

Assumption: your SQL Server was installed on remote server and behind firewall; SQL Instance was started; and  your client app specify correct remote sql instance name.

On your server side:

[1] Enable remote named pipe or tcp: All programs | Microsoft SQL Server 2005| Configuration Tools | SQL Server Surface Area Configuration | Configuration for Services and Connections | Remote Connections, choose either enable TCP or Named Pipe or both.

[2] Sql Instance was restarted successfully, check Server ErrorLog, find which tcp port or pipe name server is listening on.

[3] netstat -ano | findstr <portnumber> if server enable TCP, and make sure server is listening on the correct port.

[4] go to services.msc, find service "SQL Server Browser", enable it and restarted, also, go to SQL Server Configuration Manager, check properties for SQL Browser service, in Advanced tab, make sure it is active.

[5] Enable "Fire and Printer Sharing" in Firewall exception list.

[6] Add TCP port or sqlservr.exe to Firewall exception list, either add "..Binnsqlsevr.exe" or add port.

If your server was not started successfully by any reason, it is very helpful to collect info from server logs; also, you can get clear picture of protocols that server is listening on, for eg, if TCP was enabled, you should be able to see which port server is listening on, and if Np was enabled, you can make connection throgh the pipe name.

[7] Add Sql Browser service to Firewall exception list, you can either add program " C:Program FilesMicrosoft SQL Server90Sharedsqlbrowser.exe" or add UDP port 1434.

[8] Make sure if your remote sql Server Instance is a default instance, it must listen on tcp port 1433 and pipe \.pipesqlquery.

On your Client Side:

[1] ping <remote server> return correct IP address of your remote server.

[2] telnet <remoteserver> <portnumber> works, <portnumber> is the port that your remote sql instance is listening on.

     telnet < ipaddress> <port> works

[3] \<remoteserver>, make sure you can access share of remote server.

[4] Go to SQL Server Configuration Manager | SQL Native Client Configuration | Client Protocols, make sure Named pipe or tcp is enabled; Click properties of Client Protocols, make Sure you see at least Np or tcp is in enabled protocols, plus, recommend put TCP on the top of the order.

[5] If you are using MDAC ( Driver={SQL Server} or SQLOLEDB.x) in your client application, in command line, tyep "cliconfg.exe", also enable NP and TCP and put TCP on top of order.

[6] Use osql or sqlcmd to try " osql /S<remoteserver> /E" or "osql /S<remoteserver><Instancename> /E" see whether connection works.

[7] Check your client connection string syntax: a. do you specify correct remote server name? b. do you specify correct instance name? if remote sql is default instance, you just need to specify remote server machine name, otherwise, you need to specify " <remoteserver><instancename>" c. do you  spcify tcp port or pipe name in your connection string, if so, double check the port and pipe name are the one server is listening on, otherwise, remove it.

[8] If your client app connect to remote server using server alias name, a. if you are using MDAC, try "cliconfg.exe", in "Alias" Tab, check whether you specify any alias in which the tcp port or the pipe name should be the one remote server is listening on; b. if you are using SQL Native Client, go to SQL Server Configuration Manager, check "Aliases" configuration.

If you are sure the network protocol configuration for remote connection are all correct by going through above checklist, and still face specific problem, pleas refer following blog that give troubleshooting tips based on concrete error message:







SQL Server Protocols

Disclaimer: This posting is provided "AS IS" with no warranties, and confers no rights