So I have an application that connects to our SQLServer.
This works on any server behind the firewall just fine.
When i put it out on our live server, outside the firewall the connection to the sqlserver fails with this error
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)
I know this is due to the firewall though the network admin claims the firewall is allowing it through (has even gone to the point of saying "your doing it wrong")
What can I do to see where it is failing exactly to see if it really is the firewall and prove to him that it is.
I am using the IP of the machine so it is not a DNS issue.
Any other ideas?
With all due respect, your admin is right by telling you you're doing it wrong, assuming if what you mean by "outside the firewall" means outside of your company's network. Something like a database server should never be exposed to external connections.
Edit: Never mind, this is a connection from the DMZ.
So the only thing I can think of is to try and telnet to that machine on port 1433 (while logged into the web server) and see if you get a connection error. You're not using SSPI so I don't think security would be the issue.
If telnet fails then you can take that to your network admin as proof that the problem is the firewall.
Are you using a named instance? Make sure SQL Browsing Service is running.
Usually when you connect to the default instance on your local server you use '(local)'. When it's a named instance you would use '(local)\InstanceName'. Or (local) is replaced by a host name or ipaddress.
When you use a named instance you could run into connection problems when trying to connect from a remote server.
Related
I try to connect to remote SQL Server 2008 Express database from my ASP.NET web application but error throws:
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)
How to resolve that problem. Thanks!
Here's the first thing to check. By default Express only has the shared memory protocol enabled. You'll need to enable TCP/IP protocol for the service (SQLEXPRESS). You do this through the SQL Server Configuration Manager.
Also since Express is a named instance, you'll need to ensure that the SQL Server Browser service is started.
Make sure your connection string is correct. When you are hitting a named instance (SQLEXPRESS in this case) you need to have the data source as yourServer\sqlexpress.
And not to mention, make sure you can ping the box that houses the instance.
Check those things out and let me know if that still doesn't fix it.
i thing your connection string is not correct. Also check a named instance you try to data source as IPaddress\sqlexpress. Like 000.000.000.000\SqlExpress
I have problems connecting to my database server. The database server is not local, I am connected via its IP address.
It works fine in my development machine. After publishing the website to my server, it can not connect to my database server.
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)
Why can't my publish server connect to the database server, whereas it works fine through the development machine?
I often had that problem. Mostly it's because of two problems.
Open the SQL Server Configuration Manager.
Check if the SQL Server Network Configuration supports TCP/IP, if it's disabled, enable it.
e.g. SqlServer 2005 Network Configuration, Protocols for SQLEXPRESS
Open the SQL Server Management Studio
Click on the Sql Server Properties (right click on the server name and
select properties).
After that, select the page "Security" and switch the check to "SQL Server and Windows Authentication mode".
That's all.
I'll attempt to go two for two on the psychic debugging for today...
I will assume that you are not using integrated security? If so it might explain things as the account on your local machine probably has permissions, but the SYSTEM account that is running on the server does not. Just a shot in the dark though.
It sounds like your server can't make the network connection, rather than a security issue.
Ensure that any firewalls on both the DB and app servers allow traffic on the port (1433).
Ensure you're able to ping or tracert from both machines.
Is it your first time you publish your website on the web server ? if it is , Are you sure you have set your connection string properly ?
You need to create a login ( of curse a password for that too ) and the IP Address of that SQL on the web server .
So you need IP Address of the sql server host , Database Name , UId , Pwd .
I will agree that this sounds like a network issue and not a security issue.
Remote into the web server and ping the DB server by IP address. If this does not work, your server cannot see the DB server via that address (different subnet, incorrect firewall/proxy setup, etc). There may be a proxy address you must use to get to the DB server from the web server, or your web server may also be the gateway and IIS doesn't know to look for the DB server on the LAN. If it does work, the computers may not be talking on the same port, or the firewall may be blocking that port exiting the web server.
I have spent hours trying to connect to SQL server using sqlcmd. I disabled my firewall, checked all ip listed in "Protocols for SQLEXPRESS", edited my hosts file. I tried using different ips and machinename to connect to the server. But none of work worked. After hours of investigation, I found out that I made absolutely stupid blunder making me unable to connect.
I want to remind people that the connection string is not case sensitive. But the option is!!
what i did is I put
sqlcmd -s .\sqlserver
But the correct string is
sqlcmd -S .\sqlserver
so watch out, people
I will get the error below randomly when I'm running an asp.net application I am working on. Usually it will happen ever 3 days or so and I am forced to restart my machine to fix it but it's been getting worse and now a reboot dosn't seem to fix anything. I'm running the application on my machine and doing a lot of debugging. All interactions with the db are done through linq to sql. The db is on another server that I am connecting to. Has anyone run into this before? Any suggestions?
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 - No such host is known.)
It may be DNS, try to use some different DNS addresses. :)
I've seen similar before but it was related to a faulty network card that was dropping packets. Have you had any other strange network problems?
In your connection string to the db is the host entered as a hostname or an IP address. If by name try swapping to its IP address instead. This won't solve the underlying problem by may workaround it for you.
Edit
Also have a look at this SO answer here. Are you leaving connections open/orphaning them? That would ring true with the disconnect happening at regular time intervals..
I was wondering if there is a way to see if a server blocks outgoing connections. I am trying to connect to an external database from a client's server.
This is the error I get:
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.)
Edit:
I forgot to say I only have access to the plesk control panel. That's why I was asking if there is a way with asp.net.
When you say "server", do you mean the asp.net server, or the SQL server? And are both machines on the same network? Is this hosted?
Sql Server:
They can remove the OPENROWSET functionality, so you can't connect to remote servers, regardless
I doubt they are giving you access to linked servers in a hosted env
ASP.Net
You can try to connect to the other server via a regular connection, and see if that works.
Download a tracert component, and use that to try to trace from your server to the remote one.
If it dies somewhere inside your network, then that is your answer (it is blocked)
If it works, the outbound is open. Doesn't mean 1433 is open though.
If it dies after, not blocked, but maybe the remote is blocking icmp echo
Remember to try to tracert to somewhere else that you know works
It will be hard to tell what is killing the connection on 1433, if you can get to the server using other means. Could be the firewall, their fw, etc.
The trusty telnet method:
telnet theserver 1433
If this times out, the server is not listening. If the screen blanks and you can type something, the server is listening and no firewall is blocking the connection.
In Vista and Windows 7, you have to install telnet as a Windows component from Control Panel -> Programs and Features.
I have a login page that works in my local development environment. When I push the site onto the web server, i am getting this error when trying to login from the asp.net login control.
An error has occurred while establishing a connection to the server. When connecting to SQL Server 2005, this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
I cannot figure out why it does not work on the server. Do I need to add anything or change something in the web.config?
This support article may help. It may also be a firewall issue or an authentication issue on the new setup (but the error message makes that less likely).
For resolving error 26 in sql server you need to do the following steps.
At Server System
1. Under surface area configuration manager-Open up remote connections.
2. Add into firewall 1433 and 1434 port no as n exception.
3. Open port 1433 on router for WAN access.
4. Add client machine ip address as an exception to your antivirus or allow LAN settings in antivirus.
5. Now try to check if both client and server are connected to each other.
for this type "ping IP address of remote system" at run and if reply is obtained then do same for server machine.
If reply is obtained from both machines.
Open Sql server and try to connect to remote machine which allow remote connections using its ip address. U will surely get connected to server machine
See this video
Check to make sure TCP/IP is enabled on the SQL Server. For whatever reason, named pipes and TCP/IP is off by default. Also make sure you are trying to connect to the correct instance (maybe you are using ./SQLEXPRESS locally and on the server SQL is installed on the default instance). Lastly, make sure the database you are trying to connect to exists on the server.