I have a server with:

  • Windows 2008 Server
  • SQL Server 2008 enterprise

From my server using SQL Server Management Studio, I can't logon to any SQL Server and vice verse, I can't connect to my SQL Server from any pc/laptop.

I checked and see that, the port 1433 closed, even if I turned of firewall, I still can't connect to it.

My server name is: S143343. I have 2 sql server instances is MSSQLSERVER and S143343 (the same name with server name for replication). But I can't start S143343.

One more thing, from my server, I just connect to sql server by server name is localhost or dot (.). No way to access by computer name or IP.

Can you show me the way to solve this problems?


2 Answers 2


I'd check Services to ensure both are running - the name in Services for both SQL Servers will also confirm the instance name. On my laptop, I have MSSQLSERVER, so I can connect to that with either the machine name (LAPTOP), or with . My other instance is called SQLTEST2, so I can connect to LAPTOP\SQLTEST2.

If that fails, go looking in both sets of binaries in Program Files. Each instance will have ERRORLOGs in the the respective log folders - that might have a clue in there, such as a login error.

Incidentally, since they are both on the same machine, ensure Shared Memory is enabled for both.


If I understand correctly from your description, you have installed a default instance and a named instance on your server machine. - is that correct?

Port 1433 needs to be open for incoming traffic to the server which SQL is installed.

Under the SQL Server Configuration Manager (on your server) ensure :

  • The Sql Server service is "running"
  • Also that TCP/IP is enabled for both instances (find this under "Sql server network configuration")

Did you install SQL in mixed mode? or Windows Authentication? Which login are you using on Sql server management studio? What are the errors you get?

Its hard to answer if your problem description is not clear! Please see the link below as it will help you to ask better questions: https://dba.stackexchange.com/questions/how-to-ask

  • you have installed a default instance and a named instance on your server machine -> YES. Port 1433 -> I can't open it, even if i turned of firewall. TCP/IP is enabled!. I'm using mixed mode. I login using SQL account (sa account). Error: I can't start named install together with default instance. If I stop default instance, I can start named instance , but connectionstring with server name is localhost or dot (.) can not run with named instance, only by default instance.
    – vNext
    Nov 12, 2011 at 8:38
  • You say you get an error but you haven't given us an error message!? When trying to connect to a named instance you can use "S143343\S143343"
    – VDMT
    Nov 12, 2011 at 8:54

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