I am trying to connect to a SQL Server database that is behind a firewall. The asp.net application which is in the DMZ tries to connect to the database, however I am getting an error (The webapp works fine from my local machine):
When I telnet:
open 0.0.0.0 1433
it says:
Connecting to 0.0.0.0 ...
Connection to host lost
Does this mean that the firewall is blocking the incoming request? Or is this something else? (IT support assured me the port is open)
Connection string:
data source=0.0.0.0; initial catalog=mydb;user id=xxxx;password=xxxx;persist security info=True;packet size=4096;
Create a new UDL file on your ASP server. Open the UDL file, use the interface to successfully connect to the SQL server and save the file. Open the UDL file in a text editor and copy the connection string into your application.
If your sql server is behind a firewall (and it's a good thing that it is), then your web app should not be connecting to it directly. Rather, it should be going through some sort of service layer. That can be implemented in a variety of ways with different technologies. This service should be located physically on a machine that can access the db, and the web server should not be allowed to directly connect to the db machine (or cluster).
So, with that said, let's address your connection string. Try adding 'integrated security=true'. Here's an example:
<connectionStrings>
<add name="ConnStringDb1" connectionString="Data Source=MY_SERVER_NAME_OR_IP;Initial Catalog=MyDataBaseName;Integrated Security=True;" providerName="System.Data.SqlClient" />
</connectionStrings>
Again, it's important to note that the web app itself should only be calling to this service layer (perhaps WCF, or possibly a COM component), not connecting to the data access layer directly. There are lots of samples on how to design these types of applications. Here's one that hopefully may help. http://www.c-sharpcorner.com/UploadFile/SukeshMarla/3-tier-architecture-using-Asp-Net/. Good luck.
Related
I have sqlexpress installed on my dev laptop along with vs2019. I can access the sql instance in both SSMS and from the Server Explorer. When I go to debug and asp.net project, the sql connection fails with:
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: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
This same configuration works on my desktop - same connection strings - no problem. And laptop sql is configured to allow remote connections.
Not sure what to do next?
Thanks
Abbott
Additional Info ...
I made sure the named pipes and tcpip were enabled and browser was working. Still had same error. Here are the connection strings. The desktop connection works on my desktop:
<!--Local DB For Desktop Testing-->
<!--<add name="DBConn" connectionString="data source=DESKTOP-QQOLG5N\SQLEXPRESS;initial catalog=kidsbookoutlet;integrated security=SSPI;persist security info=True;packet size=4096" />
<add name="KBODataEntities" connectionString="metadata=res://*/Context.KBODataEntities.csdl|res://*/Context.KBODataEntities.ssdl|res://*/Context.KBODataEntities.msl;provider=System.Data.SqlClient;provider connection string="data source=DESKTOP-QQOLG5N\SQLEXPRESS;initial catalog=kidsbookoutlet;integrated security=True;multipleactiveresultsets=True;application name=EntityFramework"" providerName="System.Data.EntityClient" />-->
<!--Local DB For Laptop Testing-->
<add name="DBConn" connectionString="data source=LAPTOPDELL\SQLEXPRESS;initial catalog=kidsbookoutlet;integrated security=SSPI;persist security info=True;packet size=4096"/>
<add name="KBODataEntities" connectionString="metadata=res://*/Context.KBODataEntities.csdl|res://*/Context.KBODataEntities.ssdl|res://*/Context.KBODataEntities.msl;provider=System.Data.SqlClient;provider connection string="data source=LAPTOPDELL\SQLEXPRESS;initial catalog=kidsbookoutlet;integrated security=True;multipleactiveresultsets=True;application name=EntityFramework"" providerName="System.Data.EntityClient"/>
Here's the ssms connection that works.
Do you have the sql server browser service running? Usually SSMS will complain, and since that is working, then this is a long shot. But I would ensure that not only is sql server service running, but also sql browser service.
This one:
Next up? Which provider in .net are you using to connect?
You have and can choose:
oleDB
ODBC
sqlProvider <- recommend this one
So, I would in the project settings, create a connection string here:
And for above, did you try the test connection button when you use the connection string builder:
This one:
I mean, why try running a bunch of code and all kinds of stuff. Now maybe you ARE talking about the conneciton builder in VS, and you can't connect.
However, if SSMS can, then VS should be able to.
So, does the test in above not work?
You can also try (and should) in the sql confi check the above screen cap if the browser service is running. And while you doing that, check the connections.
Expand the SQL Server Network Configuration
and look at these settings:
So before you write any code?
You check if browser service is running. Click/expand Protocols for sql express.
Then in VS you launch the connection builder and use the test connection.
All of the above is done in aobut 40 seconds tops of your time.
And these steps are quite much the first thing you will do.
Don't try and write code in VS just yet. Use the connection string builder.
You also failed to mention which provider you are using? (this is VERY troublsome, since you supposly dealing with conneciton problems, and you FAILED to mention what provider you are attempting to use.
As noted, you have 3 choices:
oleDB provider
ODBC provder
sqlProvider (this is the recommend .net provider - often called ado.net (but I NEVER know for what reason - that term should have been banished long ago for the poverty and confusing it caused over the years).
Anyway?
Spend 45 seconds checking the above, and then an additional 35 seconds creating a connection in VS. Just remember to choose the SAME provider in that connection builder as you using in code (1 of the above 3), and thus when you use test connection, you at least have a known working connection string, and a known working connection string for the given provider you are using here.
I'm creating an ASP.NET application for my company.
In Visual Studio, I used EntityFramework to connect to my SQL Server database with an edmx file. The application is using Windows authentication to connect to both the website and SQL Server.
When I run the application locally, all is working great. The Windows authentication works so my app know who I am, then it connects to SQL Server correctly and shows up data.
But when I try to deploy it on my IIS Server, I get the following error :
Login failed for user 'DOMAIN\SERVERNAME$'.
The Windows authentication works great to identify who I am in the app, but the integrated security used to connect to SQL Server is using the server identity instead of the identity of the application's user.
What you may want to know :
All users have an SQL Server account to connect through integrated security
The server is on the same Domain than our computers
The SQL Server is on another server than the machine where IIS is running, but the remote connection is activated and working
I'm using Google Chrome to test my app locally and remotely
There is the connection string I am using :
<connectionStrings>
<add name="DatabaseEntities" connectionString="metadata=res://*/Models.DatabaseModel.csdl|res://*/Models.DatabaseModel.ssdl|res://*/Models.DatabaseModel.msl;provider=System.Data.SqlClient;provider connection string="data source=SQLSERVERNAME\INSTANCE;initial catalog=Database;integrated security=True;multipleactiveresultsets=True;application name=EntityFramework"" providerName="System.Data.EntityClient" />
Is it possible to use the same Windows authentication for both ASP.NET application and SQL Server ?
You should add your domain user to SQL-server logins - look here
Or remove integrated security option from connection string and add user id and password of sql server user:
<add name="DbConnectionString" connectionString="Data Source=SERVER;Initial Catalog=db;User Id=sqlusername;Password=sqluserpass;MultipleActiveResultSets=True;App=EntityFramework" providerName="System.Data.SqlClient"/>
note that exampled connection string does not contains metadata for model-first approach
I was looking on how to set this up for SQL FILESTREAM in my API.
Update the Host File with the IPV4 for the FQDN or SERVERNAME of the SQL Server.
In Credential Manager add 2 Credentials.
One for File Share the other Port 1433.
The File Transfer does not require the Domain, but the Port 1433 version does.
After this was able to use Trusted Connection or Integrated Security=SSPI to access the FILESTREAM.
I have an ASP.NET 2 (very old) web app that I am trying to migrate to a new server. BTW, I am a complete ASP.NET noob but have a good amount experience with other web technologies.
In the web.config, I can see the following connection string XML:
<connectionStrings>
<add name="myCon"
connectionString="Data Source=DEVELOP\DEV_SQL2008R2;Initial Catalog=QO2_New;Persist Security Info=True;User ID=sa;Password=q"/>
</connectionStrings>
I did "nslookup" on the machine name 'DEVELOP' and RDP into the server. To my surprise, I don't see any SQL Server process running. Also, there is no SQL Server installed on that server. I am 100% that the app is running and I am very confident that there are content that comes from the database. I also did a search on the code base and it seems like the connection string is being used.
On a side note, we do have some other databases on separate machines. My questions are the following:
Can the machine DEVELOP somehow redirect the DB connection to somewhere else? If yes, how do I find out which IP is it being redirected at?
If DB connection cannot be redirected, then what is going here exactly?
Unfortunately, I have very little people whom I can ask what is going with this app. Any tips that you can share is much appreciated.
Nslookup uses DNS but there is a chance your machine has a hosts file entry that points DEVELOP to somewhere else..
However, if you RDP'ed into DEVELOP (as in, used that name when connecting RDP, not the ip address given by nslookup) then you should have been able to see a sqlserver install in the list of services.
If there is surely no sqlserver installed there then, from within your RDP session, use TCPView from sysinternals to see what process is listening on port 1433. Could be some kind of TCP redirector like PortTunnel from SteelBytes, bouncing the connection somewhere else. Remember to run tcpview on the server, not your local machine
Perhaps you can try getting connected to the sqlserver using management studio, using the credentials in the web config, you can get sqlserver itself to tell you more about where it is running, such as:
SQL - Query to get server's IP address
Using Environment variables in T-SQL
I am truly ashamed to inform everyone that the database in the web config was never being used. Therefore, even though it is pointing to a non-existing database, it still works. The data from the old database have been converted to static files.
I should have checked this the first thing I came across it. Thanks again for all the help.
I want to connect asp.net application hosted at a web server with sql server 2012 db hosted at another remote location.
I have enabled the TCP/IP on sql server, also set port 6322 for ip1 and ipall.
but if i go to my web server and telnet into the db server, no connection is established.
in ASP.net page just to test the connection i am using the connection string as below
<add name="DBConnectionStringTEST"
connectionString="Data Source=<db ip address>; Initial Catalog=<db name>; Persist Security Info=True;User ID=<username>;Password=<password>;connection timeout=0;Max Pool Size = 100;Pooling = True"
providerName="System.Data.SqlClient" />
my questions,
1) is there something i am missing, like wrong port.
2) do i need to give db ip address(client_net_address) or the actual db server address.
3) do i need to ask the server administrator to allow web server ip address to connect.
4) what is the quickest way to test if the web server can talk to the sql server without having to amend the connection string in asp.net application every time i make changes.
NOTE: i have searched other similar topic but couldnt find any answer which worked for me.
Without an explicit port or instance name specification, the default 1433 port will be used. Specify your custom port in the connections string:
<add name="DBConnectionStringTEST"
connectionString="Data Source=<db server ip address or host name>,6322; Initial Catalog=<db name>; Persist Security Info=True;User ID=<username>;Password=<password>;connection timeout=0;Max Pool Size = 100;Pooling = True"
providerName="System.Data.SqlClient" />
An easy way to test network connectivity is with TELNET:
TELNET <db server ip address or host name> 6322
This will show an empty console window if successful. Press ctrl-C to close.
You can also verify port connectivity with the Powershell command below if you don't have TELNET installed:
6322 | % { echo ((new-object Net.Sockets.TcpClient).Connect("<db server ip address or host name>",$_)) "server listening on TCP port $_" }
1) is there something i am missing, like wrong port.
From your posted connection string it looks like you are using default instance. if it's indeed named instance then provide the same info in your connection string.
2) do i need to give db ip address(client_net_address) or the actual
db server address.
It should be actual DB server IP address/Hostname along with Db server installed instance name.
3) do i need to ask the server administrator to allow web server ip
address to connect.
If you are providing correct IP addr/hostname/port/credential then it should allow you to connect through. (provided your DB admin have already created DB user for you)
4) what is the quickest way to test if the web server can talk to the
sql server without having to amend the connection string in asp.net
application every time i make changes.
By creating a UDL file. Open a notepad and save it as test.udl. Once saved -> double click the file -> provide all info and test the connection. It should look like below
EDIT:
To configure a universal data link (.udl) file
Double click on he file named test.udl
On Provider tab select SQL Server Native client 10.0
On Connection tab
enter BRR=SQL-N1 as Server Name
In Username and password section provide SA and password
Click on Test Connection
See Here for more information on this.
We are upgrading from an environment where the development web server, the SQL Server 2005, and SQL Server data are all on the same machine, a Windows XP Machine. We are upgrading to having the web server on one Windows 2008 server, the SQL Server on a 2nd Windows 2008 Server, and to Server to a Windows 2008 server, nd the data on a SAN.
Now we are getting the error message:
A connection was succesfully established with the server, but then
an error occured during the login
process. (provider: named pipes
provider, error 0, no process is on
the other end of the pipe.)
The network guy thinks it is a problem with the connection string:
<add name="CNString"
connectionString="Data Source=WEBSERVER;
Initial Catalog=PCIdb;
User ID=sa;Password=pass;"
providerName="System.Data.SqlClient"/>
Can anyone help out here?
Is your SQL Server really called WEBSERVER (DataSource="WEBSERVER") ??
Also, I would never EVER use the sa account in a connection string - NEVER, period. Use an application specific user or something, but do not use the sa account under any circumstances.
This can be caused by any number of reasons, but the first thing to look at is the configuration and setup of the SQL Server itself.
Are named pipes enabled on the server? You can check this through the server configuration manager (on the SQL Server machine itself).
Is the user on the connection string (or the connection pool user if you are using SSPI) setup on the server?
Note:
I do hope the connection string you put up is an edited version of your real one, as there are a couple of issues with it:
Using the sa login - you should never do that as now any SQL exploit can do any damage it wants
Calling a sql server "webserver" - a really confusion naming decision
When it comes to connection strings, look at connectionstrings.com - they hold a good list of valid connection strings to many databases using different providers.
I got that error before...Make sure SQL server services are started
If that's not it, change the authentication mode to both server and windows.
It could be a connectionstring problem. Try comparing your connectionstring to the connectionstrings at http://www.connectionstrings.com but it could also be that the remote connection or the remote server (the webserver in this case) isn't allowed to connect to SQL.
Check if remote connections are allowed and named pipes and/or TCP/IP protocols are enabled on the database server.
But, based on the scenario you've described, I'd say it's the database-end that's refusing the connection (since you've already had a working solution).