I am developing a program with C# and WPF. I want the data to be stored in an SQL Server database. I made a connection string with the instance name in my PC, and that worked. But when I want to connect through the Internet with an IP address, I get some errors:
A network-related or instance-specific error occurred while
establishing a connection to SQL Server. The server was not found or
was not accessible Verify that the instance name is correct and that
SQL Server is configured to allow remote connections. (TCP Provider,
error 0 - No connection could be made because the target machine
actively refused it.)
I enabled TCP/IP, allowed remote connection in SQL Configuration Manager, opened a port of 1433 in my firewall, but still I am getting this error.
My connection string is this:
String connString = #"Network Library=dbmssocn;
Network Address=127.0.0.1,1433;
Integrated security=SSPI;
Initial Catalog=db";
SqlConnection conn = new SqlConnection(connString);
conn.Open( );
Where is my mistake?
There is very slight error in your connection string and honestly I can't blame you for that as it is very weird way in which SQL Sever is behaving. I'm not sure if this error lies in connection provider side or SQL Server instance side. Name of Network Library that your application is using to connect to the SQL Server using dbmssocn(Win32 Winsock TCP/IP) should always be mentioned in capital letters. Though I didn't see any relevant MSDN documentation from MS to support my statement but it actually worked when I did so. Here is the connection string that you should be using to fix the error.
String connString = #"Network Library=DBMSSOCN;
Network Address=127.0.0.1,1433;
Integrated security=SSPI;
Initial Catalog=db";
Seriously, I got freaked out in reproducing your issue as instead of copying the connection string from your question I copied it from some other blog :). But all is well that ends well. I've also assumed that a database named "db" actually exists on the default (NOT named instance) instance of the sql server you are connecting to when typing this answer. If changing the casing of network library name in connection string doesn't help then double check that database "db" must exist for a sql server default instance to which you are connecting to. In case you are using a named instance of sql server in your installation then that instance name should also come in the connection string.
Configure your SQL Server to allow TCP/IP connections. Go to SQL Server Configuration Manager -> network then protocols for your SQL Server named instance -> TCP/IP.
See this image!
Related
This application that i am trying to create, whose "instances/copies" will be installed on multiple PCs of the client and are able to access the same database from another PC of the same client that has SQL server running all the time through the same network(i.e: they have the same router and static IP of server etc).
I had two ways to do this:
To make applications use the same database through synchronization.
To have multiple localdbs that then share the changes a database server.
By following 1st way,
I tried setting up the Connection String like:
SqlConnection con = new SqlConnection("Data Source =[serverPcIP,Port];Integrated Security=True;Connect Timeout=30");
SqlConnection con = new SqlConnection("SERVER=[serverPcIP]; Port=[portno];Integrated Security=True;Connect Timeout=30");
In Server - Security Settings:
I have allowed "SQL Server and Windows Authentication mode"
In Sql Server Configuration Manager > SQL Server Network Configuration > Protocols for SQLEXPRESS => TCP/IP = Enabled; under IP Addresses -> IP1 -> TCP Port = 1433 (port that i used in my connection-string)
In advanced Firewall Setting:
Have enabled the Incoming & Outgoing rules for port 1433.
The exception that i get:
Additional information: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: TCP Provider, error: 0 - The wait operation timed out.)
Can someone please tell me what configurations (either in connection-String or in SQL server itself) am i missing?
Your connection string lacks the instance name e.g. data source=<hostname or ip>\SQLEXPRESS. If your database listens on the default port 1433 you don't need to pass that with the connection string
If you setup a SQL server, you can choose between the default SQL Server instance or the named instance. For SQL Express the default is to install a named instance with the name SQLEXPRESS. If you don't use the default instance and install a named instance instead, you have to pass it with the connection string.
The default SQL Server instance ist just a named instance with the well known name MSSQLSERVER. So if you installed the database instance as the default instance you can connect with <host>[,port] or <host>\MSSQLSERVER[,port]
based on your screenshot, under IP1, the ip address is active but not enabled.
also, ip address that starts with 169.x.x.x normally would mean you have set up this network card to use DHCP, but the network card failed to have ip address from the DHCP server.
do you mind try to use static ip address?
Consider following steps:
Since you mention the port number using configuration manager, the service required restart. please restart the service if not done so.
Seems you are able to connect via SSMS, once service restarted verify SQL Error log via SSMS -> Managemnt -> SQL Server Logs, you must find a message as follows:
Server is listening on [ 'any' <ipv4> 1433].
Further details, follow these steps. Also, this..
I am currently implementing a UWP program for an existing database. I took this article as a basis.
https://learn.microsoft.com/en-us/windows/uwp/data-access/sql-server-databases
When running, I get an exception:
System.Data.SqlClient.SqlException" в System.Data.SqlClient.dll
Exception:
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: TCP Provider, error: 25 - Connection string is not valid)
This seemed strange to me, since a WPF application with the same connection string works fine. Next, I decided to install a database instance on my computer and export some of the data to a local database. To my surprise, after replacing the connection string from:
Data Source=sqlserver\sqlexpress
to
Data Source=.\sqlexpress
UWP program read this from the database on my computer.
I also read this article to make sure that the remote database is configured correctly. https://www.lansweeper.com/knowledgebase/a-network-related-or-instance-specific-error-occurred/
As I said, WPF programs work with this database perfectly. What are the ways to check why the UWP doesn't want to communicate with the database?
to make it clear whether the remote server is available in principle, I apply the output of the TNC command:
tnc sqlserver -p 1433 -I detailed
ComputerName : sqlserver
RemoteAddress : 192.168.10.11
RemotePort : 1433
NameResolutionResults : 192.168.10.11
MatchingIPsecRules :
NetworkIsolationContext : Private Network
InterfaceAlias : Ethernet
SourceAddress : 192.168.10.20
NetRoute (NextHop) : 0.0.0.0
TcpTestSucceeded : True
Connection string look like:
private string connectionString = #"Data Source=sqlserver\sqlexpress;Initial Catalog=TestCatalog;User ID=*;Password=*";
The same connection string is used in VS. VS shows the contents of the table without problems. I can also delete or add new lines in the VS editor.
I'm talking about a remote database. In VS server Explorer I have a Data Connection where I am connected to a remote database. I can safely edit remote database data in VS (add, delete and update). I see the connection string and originally used it as the connection string in UWP app.
You have already taken a look at this microsoft link here. Long story short, have you followed the proposal below?
Trouble connecting to your database?
In most cases, some aspect of the SQL Server configuration needs to be changed. If you're able to connect to your database from another type of desktop application such as a Windows Forms or WPF application, ensure that you've enabled TCP/IP for SQL Server. You can do that in the Computer Management console.
Check to see if you have followed the rest of the solution properly. You might need to enable the tcp port from the window firewall.
Go to firewall -> Inbound Rules -> Add TCP:1433 in the rule.
Also since the error is about the connection string, try to use only the server name/ ip/ or hostname, without the server instance.
You can also add the port number and see if this works for you. When you add it, sql server ignores the instance name (as different instances require different ports to work, so it can work as a unique identifier).
Edit: How to create a valid connection string:
Look at this answer here: How to get the connection String from a database
What connection string should I use if SSMS connects to it using simply machine name, without instance name?
I mean it connects using the following string: PCName
I used to connect using PCName/SQLExpress. I cannot set correct connection string in my app in order to connect app to database on this machine.
How can I check what data source I should use? I've checked in Sql Server configuration that server instance named as SQLEXPRESS.
So I tried data source as:
.\SQLEXPRESS
PCName\SQLEXPRESS
.
I'm trying to connect to a service-based database, located in my app folder. So I'm using the following connection string:
data source=PCName;attachdbfilename=|DataDirectory|\spareparts.mdf;integrated security=true;user instance=true;multipleactiveresultsets=true;App=EntityFramework;
If SSMS connects via PCName then your application should be able to use Data Source=PCName. However it depends on whether your application is on the same machine as SSMS or not. If on a different machine it might not be able to connect for a variety of reasons. We can't speculate what the problem might be if all you do to describe the issue is "It won't connect" - what does that mean? Do you get an error message? If so, what is it? Make sure:
SQL Browser service is started
TCP/IP is enabled
Add Network=DBMSSOCN; to the connection string
You've also tried the IP address in addition to PCName
Firewall isn't blocking the SQL Server port
What I want to do is an application that uses a SQL Server 2008 database, but I can't manage to connect to the db.
Here is my code:
public Form1()
{
InitializeComponent();
connection = new SqlConnection("Server=(local);Integrated Security=true");
connection.Open();
CreateDb();
this.FormClosed += new FormClosedEventHandler(Form1_FormClosed);
}
The error that I'm getting says:
A network-related or instance-specific
error occurred while establishing a
connection to SQL Server. The server
was not found or was not accessible.
Verify that the instance name is
correct and that SQL Server is
configured to allow remote
connections. (provider: Named Pipes
Provider, error: 40 - Could not open a
connection to SQL Server)
I am trying to connect using windows authentication...
What am I doing wrong?
Check that TCP/IP connections are enabled in the SQL Server Configuration Manager. Also, if you have installed it as an instance, you will need to specify the server name as .\INSTANCE_NAME.
Try this one :
Data Source=localhost\MyInstanceName;Initial Catalog=myDataBase;Integrated Security=SSPI;
Your instance name is probably SQLEXPRESS or MSSQL (unless you called it something else).
You can find connection string examples on this page:
http://www.connectionstrings.com/
Sounds like either SQL Browser isn't started or isn't configured to respond.
You didn't mention if you're using express or the full blown version... But that probably doesn't matter as the steps are pretty much the same:
http://www.symantec.com/connect/articles/install-and-configure-sql-server-2008-express
Assuming everything is actually installed, start with the "Enable TCP" section.
Serverfault is an excellent source of help on problems like this.
Try suggestions from threads like:
https://serverfault.com/questions/11745/i-cannot-connect-to-my-local-sql-server-2008
https://serverfault.com/questions/94923/a-network-related-or-instance-specific-error-occurred-while-establishing-a-connec
https://serverfault.com/questions/75048/sql-server-connection-issue
https://serverfault.com/questions/111789/how-to-connect-to-local-instance-of-sql-server-2008-express
Most of them suggest checking that the service is running, checking the firewall, checking the user, etc
There are lots of threads matching - search
Although it talks about sql express, this thread looks particularly helpful - https://serverfault.com/questions/191576/sql-server-cant-connect - lots of things to try
I have an MS SQL Server 2005 Express running on a VPS.
I'm using pymssql in Python to connect to my server with the following code:
conn = pymssql.connect(host='host:port', user='me', password='pwd', database='db')
and it works perfectly.
When I try to connect to the server from an ASP.NET C# page with the following code:
SqlConnection myConnection = new SqlConnection("Data Source=host,port;Network Library=DBMSSOCN; Initial Catalog=db;User ID=me;Password=pwd;");
myConnection.Open();
When I run the ASP.NET page I get the following exception at myConnection.Open();:
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: TCP Provider, error: 0 - A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.)
I tried restarting the SQL Server but I had no luck.
Can anyone point me out to what I'm missing here?
Thanks!
Let's say your host is localhost. When you are using SQLEXPRESS you need to specify that in your Instance Name.
Loke this: Data Source=localhost\SQLEXPRESS if it is bound to localhost. Otherwise it might just work with: Data Source=.\SQLEXPRESS.
If you have management studio installed you can fire that up and check what connection string it is using!
Still doesn't work..
I'm able to connect to the remote server with SQL Management Studio.
I enter host,port\SQLEXPRESS (of course I my actual IP number as the host and my actual port) in the Server Name field, select SQL Security and enter my username and password and it works perfectly.
When I try to connect from the ASP.NET page, it just doesn't work - I get the error aforementioned. Can it have something to do with the company hosting my asp.net page? (GoDaddy)
here is the code again..(assuming my host is 11.22.33.44 and my db is named bla
string connectString = #"Data Source=11.22.33.44,1433\SQLEXPRESS;Network Library=DBMSSOCN;Initial Catalog=bla;User ID=username;Password=pwd;";
SqlConnection myConnection = new SqlConnection(connectString);
myConnection.Open();
Thanks again