Hi all,

I'm receiving the error: "[DBNETLIB][ConnectionOpen (Connect()).]SQL Server does not exist or access denied." when connecting to the SQL Server.

The strange thing is that in general establishing the connection isn't a problem but so now and then this error pops up.

I'm using SQL authentication over a TCP/IP connection which are defined in an UDL file. We've tried connection using a DNS name or an IP number but that doesn't matter.

I'm using:
- MS SQL Server 2000 sp3
- IIS 6.0
- ASP
- MDAC 2.6

can anybody help me out?
TIA

Cheers,
Friso

James,

Not sure if this will help but I have had a simular problem when connecting to SQL Server 2000 from Visual C++ with the following:

m_csDataSource = "Provider=sqloledb;Data Source=XPPROSQLSERV;Initial Catalog=Parts;Integrated Security=SSPI;";

The problem is that "Initial Catalog" is the name of the .mdb file and it IS CASE SENSITIVE and will NOT connect if case is not exactly the same as .mdb file

HTH

Jim

I think I had the same error a while ago. There were no problems after the connection was made to a tcp/ip address instead to a computer name.

We're having the same problem... we also have the same hardware/software configuration described. If anyone has solved this issue your advice would be GREATLY appreciated...


[DBNETLIB][ConnectionOpen (Connect()).]SQL Server does not exist or access denied.


The error pops up randomly throughout the pages of our site(s).

Thank you in advance.

This is a timeout issue. Either your SQL sever is taking too long to reply to the request or something else is taking too long- like DNS resolution.

Hal Levy
Web Developer, PDI Inc.

NOT a Wiley/Wrox Employee

Thanks Hal,

We changed all connection strings to the IP Address of the SQL Server instead of "sql1.site.com". However this did NOT correct the problem.

Again, this error is random, meaning if you refresh 10 times, 3 will have an error somewhere on the page where it's opening a recordset with the existing connection. The connection is opened at the beginning of each page, and closed at the end of the page. While it's open we might open and close 10 recordsets.

Any other ideas???

I'm not sure how many times you use it matters. Each time you open a conection it needs to connect to the machine. Sounds like your SQL server is overloaded or has too many connections and it's not replying in a timley manner.

I had this similar kind of this with long running queries tying up the SQL server. You might want to check the performancve of the server through the PerfMon tool in Windows SErver.

Hal Levy
Web Developer, PDI Inc.

NOT a Wiley/Wrox Employee

In our case it's definitly not a time-out issue on the SQL Server. The error even pops up when there's minimal load.

In the security event log a "failure audit" is entered whenever we receive the [DBNETLIB] error. The website uses a SQL login defined in an UDL file but sometimes the username is lost and the connection to the SQL Server is made using the IUSR security-context.

We are using connection pooling but there is no connection from our webserver(s) which uses Windows authentication, they all use SQL authentication.

Cheers,
Friso

I have some very useful, interesting news...

We used to have the following servers in the same network:

SQLServer1
WEBServer1 (uses SQLServer1 as database backend)
WEBServer2 (uses SQLServer1 as database backend)

Whereas WEBServer1 was not having any problems at all. The problems were with WEBServer2. So we moved the top 3 highest traffic clients off of WEBServer2 and onto a new WEBServer3.

Problem temporarily solved. No more errors on any servers.

This proves that the error is not related to the load on the SQL Server, but rather the load on the Windows 2003 Web Server. Again, now we have all the same sites hitting the SQL Server box and there are no problems, all sites are fast. The question now is what exactly is not able to handle itself? Seems to point the finger at the MDAC 2.8 (the only MDAC for windows 2003, which ships with Windows 2003).

So with this in mind, what can we monitor or debug to try to find the root of the problem. It really doesn't seem like the load we had on the server was anything that should be a problem. CPU usage was always below 30%. Memory on the web server is 4GB and even after rebooting the server and having the at least 3GB free memory the error was just as bad. So neither CPU of memory are an issue.

Performance Monitor can be used to monitor all kinds of data points relating to performance- Like ASP Queues. Number of connections open.. Etc.

Based on your descriptions to date.. I'd guess your pool of connections to the SQL server is too small for the nuber required. The other options os related in that the connections to the database are not being closed in a timely manner in your code. REsulting in the pool seeming too slow to support the number of connections.

It could also be a problem with the machine itself and you might benefit from a reinstall of MDAC.


Just some ideas..

Hal Levy
Web Developer, PDI Inc.

NOT a Wiley/Wrox Employee