Unable to connect to a SQL Server named instance on a cluster


We have been seeing several occurrences where users failed to connect to SQL Server named instance on cluster. The error messages are usually as follow:

 

For SNAC:

C:>osql -E -S clusterinst

[SQL Native Client]SQL Network Interfaces: Error Locating Server/Instance Specified [xFFFFFFFF].

[SQL Native Client]Login timeout expired

For MDAC:

C:>osql -E -S clusterinst

[DBNETLIB]Specified SQL server not found.

[DBNETLIB]ConnectionOpen (Connect()).

 

In all occurrences, customers already tried some basic steps for solving similar issues, such as, enabling TCP protocol, enabling remote connection, put SQL Server named instance into firewall exception list, etc. After we tracked down to the issues, we found that it’s a combination of the specifics of Windows Cluster and the way we discover SQL Server named instance. When connecting to SQL Server named instances, our client components rely on SQL Browser to discover the server and its parameters. The discovery process is:

 

The client sends a UDP packet to SQL Browser on the target machine. When the named instance is on a windows cluster, the packet is sent to the cluster IP (or more specifically, the IP address corresponding to the virtual SQL Server). However, SQL Browser is not cluster-aware and listens on IP ANY. When SQL Browser receives the UDP request packet, it sends a response UDP packet back the client. The destination IP address is the client’s IP address, however, the source IP address is changed. It’s now the IP address for the NIC card on the physical machine, rather than the virtual SQL Server IP address. The source IP address of the response UDP packet is determined by Windows OS, based on the routing table. Because both virtual SQL Server IP address and the IP address attached to physical NIC are usually on the same subnet (thus belong to same route), physical IP address is selected preferably. Depends on the security settings on the client and server machines, this response UDP packet may be dropped because the peer IP address is changed. We have been seeing that the response packet is dropped by Firewall and/or IPSec.

 

Windows Firewall does not drop the packet. However, a third-party firewall may drop the packet. In addition, IPSec may also drop the packet if IPSec policy is enabled on the client and it can not establish a trust connection between the client and server. (Important update: If your client is a Vista machine, you will see this issue. A workaround is to specify tcp port or pipe name in your connection string directly.)

 

We decided not to fix this minor issue because it is determined by the nature of UDP protocol. A UDP socket can response to multiple senders and the socket layer never knows which one it is actually replying to. We may consider letting SQL Browser listen on individual IPs but the cost will be high. A workaround is to specify TCP port number in the connection string in which case we bypass the discovery process.

 

Please refer to the following links for additional information. The articles talk about issue for SQL Server 2000, but it also applies to SQL Server 2005 as the fundamentals did not change.

http://support.microsoft.com/?kbid=888228

http://support.microsoft.com/default.aspx?scid=kb;[LN];318432

 

*********Important update 2: regarding SQL Server 2008. ***************

We had a fix for this issue in SQL Server 2008. Unfortunately, the fix is still partial. We identify another issue which invalidate the fix on X64 machine. Other than that, the issue is fixed if the server is SQL Server 2008 on Vista/Windows Server 2008 on X86/IA64. We don’t have to do anything on the client side for these scenario. Note: the issue still applies to all version of SQL Server 2005.

 

Update3: (Mar/2009)

If you upgrade your OS to Vista SP2 or Windows Server 2008 SP2, and your SQL Server 2008 is SP1, the partial issue on X64 is fixed. Meanwhile, we identified another related issue which affect the ability to enumrate SQL instances on Vista/Windows 2008 on network . The fix is also in SQL Server 2008 SP1.

 

 

 

Xinwei Hong, SQL Server Protocols
Disclaimer: This posting is provided “AS IS” with no warranties, and confers no rights


Comments (66)

  1. trac says:

    You said that this issue won’t fix; so what do we do now (after search knowledge base for enabling TCP/IP port and some more)

  2. As I mentioned in the blog: "A workaround is to specify TCP port number in the connection string in which case we bypass the discovery process. "

    Also, you can change your Firewall/IPSec settings so that this response UDP packet won’t be filtered. E.g, put your client application under exception list of your firewall.

    Thanks.

    Xinwei

  3. Len Binns says:

    Would installing SQL2005 as a default instance (instead of a named instance) help avoid the problem?  Since you can only have one named instance per virtual server (in a clustered environment), what is the advantage of a named instance over a default instance anyway?

  4. Xinwei says:

    If it’s default instance, client can connect the server using default port number (1433). So, it’s not an issue unless you change the server TCP port.

    For the other question, Yes. One named instance per virtual server. But, you can install multiple virtual servers on one physical machine, in which case, you would need named instances so that we can distinguish those instances on the physical machine.

  5. Erik Van Reeth says:

    We do have the same phenomenon.

    When running osql on the cluster node, randomly the connection fails or succeeds.

    When doing this workaround to specify the port, than it works.

    Is this bug in SQL Browser still not fixed in the upcoming SQL2005 SP2 ?

  6. lukek says:

    would this scenario also apply to multiple instances on a host, each bound to two VLANs on two NICS?

  7. Xinwei Hong says:

    Your scenario is different. Say you have IP1 on VLAN1 and IP2 on VLAN2. SQL Instance 1 listens on IP1, SQL Instance 2 listens on IP2. SQL Browser listens on IP ALL. You can only make a SQL connection to INST1 from VLAN1 and to INST2 from VLAN2. In this case, UDP packets input/output from the same IP address on the server, so no such issue. If you try to connect to INST1 from VLAN2 or INST2 from VLAN1, you will fail. But that’s because of routing, not because of Firewall issue I described.

    Please let me know if your scenario is different than what I just assumed.

  8. lukek says:

    thanks for the feedback – our setup is slightly more complicated : SQL 2005 – two instances listening on both vlans, and one sql 2000 instance.

    We were getting intermittent prelogin failures to the SQL 2005 instances, but usage is currently light so its hard to get accurate pictures.

    I changed the bindings on the SQL 2005 instances so that they listen on only one VLAN and we still get the issue. I’m planning to simplify further as the second VLAN was only required for internet access for service pack 1.. so I’ll take that out of the equation, and hopefully that will cure the problem – otherwise I’ll have to start looking at removing the sql2000 instance.

  9. Xinwei Hong says:

    The issue I mentioned in the blog only happens when you connect one IP but the return packet changed the server IP to another one. With two VLANs, networks are seperated by lower layer(link layer). IPs usually won’t be messed up. Unless your client also attachs to both VLANs, you should not see the issue I mentioned. Also, if you do have this issue, you won’t be able to connect your server at all (without the workaround). Since you see intermittent pre-login error, I believe your issue is different.

    What’s the exact error message?

  10. lukek says:

    removing the multiple vlans has cured the problem, thanks.

    exact error message was: The SQLBrowser service was unable to process a client request.

  11. Users often see this error message when connection to a SQL Server and don’t know where to start to solve

  12. Mike says:

    So is this a bug that will be corrected in a Service pack at some point? I am hoping it is not as I have the same issue in an active active cluster each with a named instance.

    Thanks,

    Mike

  13. Xinwei Hong says:

    You can consider this as a bug for us, but its origin is the nature of UDP. We hope to fix this in coming releases. For now, you can either use the workaround I mentioned, or define an exception between your server and client on your client Vista machine. Thanks.

  14. Rob P says:

    I’m trying to register a database engine (named instance of a cluster) in SQL Server Management Studio and I can’t connect.  I also can’t connect if I drop down to osql.  I’ve added exceptions to my firewall for ports and programs but still no luck.  If I try to register or connect to the default instance of the cluster I can connect fine.  It’s only the named instance which I’m having problems with.  It also only happens on one PC.  I hate to refresh the PC if there’s a workaround.  Any ideas?

  15. Xinwei Hong says:

    Can you check my following blog about Connection Alias: http://blogs.msdn.com/sql_protocols/archive/2007/01/07/connection-alias.aspx

    Make sure you don’t have an outdated entry there on the machine you have problem. Thanks.

  16. Mark Sowul says:

    Ran into the same issue on a multihomed SQL box.  I connect using IP 1, SQL Browser response comes back on IP 2 and sure enough, the client firewall blocks it (this is on Vista).

  17. Hi, Mark

    We have a fix for this in SQL Server 2008(will be released mid this year). If your server is  SQL Server 2008 and the OS is Vista/Win2008, you will not see this issue anymore.

  18. Mark Sowul says:

    If this has been a problem since SQL 2000, how come it’s taken so long to get it fixed?

  19. Scott Monte says:

    I’m trying to connect to a clustered server (SQL 2000) with two named instances on two nodes in the cluster, and i have tried setting up sql alias entries for each, using both named pipes:

    \192.168.104.51pipe$$CACLMSDBINST1MSSQL$LMSINST1sqlquery

    and tcp

    192.168.104.51,1461

    Both of which i got from the server configuration. The IP address is the sql cluster ip address, not either named instance ip, which i believe is correct.. The other variable here is i am trying to connect through a VPN. Where should i start looking next as far as firewall rules on the other side of the vpn, etc?

  20. Jeff Bennett says:

    Does anyone see these type of login failures showing up on stand-alone servers with multiple instances of SQL 2005 and 2000 installed?  The OS is win2000 sp2

  21. On a Windows Cluster it is possible to install a SQL Server Cluster, which will be a separate entity

  22. dbrooks7 says:

    We have intermittent issues with connecting to named instances of Analysis Services on a cluster.  So, does the initial situation described by Xinwei apply in this case?  It seems that the situation described either always works or never works.

  23. dbrooks7,

    This blog does not applies your case. The discovery of Analysis Service is totally different. SQL Browser will load a dll which takes care of AS discovery.

    Thanks. Xinwei

  24. Tone Poem says:

    Top things I always forget when logging into SQL Server:   1. SSL Self-Signed Cert Does Not Work

  25. Joseph Swann says:

    Have they come out with a Fix to this yet? I’ve prefer named instances over Default but i’ve run into this problem as well and opened ports, enabled remote connections, pinged, shared drives, folders… everything short of glueing the two servers together. It simply acts as if it doesn’t want to connect to the named instance

    Have they come out with a Patch yet, or and upgrade/ fix?

  26. Xinwei Hong says:

    We had a fix in SQL Server 2008 for this issue. However, we found another issue and this issue makes the fixs does not work for x64 machine (server machine). So, if your server is SQL Server 2008 on Vista/Win2k8 on X86/IA64, you should have no problem connecting to your server even if you have firewall enabled on your client Vista/W2k8 machine. Thanks.

  27. David says:

    I have also been stalled by Error:26 issue.

    The followings are my current installed applicaions and related info:

    1. OS: Vista Home Premium with SP1

    2. SQL Server 2005 SP1 and SQWL Server Management Studio Express edition.

    3. Web Developer 2008 Express.

    Symptom:

    When I tried to create a connection to SQL Server by clciking the mdf in Database Explorer of VWD, it displayed the Error 26. However, I can attach the mdfs in Management studio and access the file at all.

    Thank you in advance for any idea.

  28. John Teutsch says:

    I am trying to connect from Server 2008×64 to Clustered SQL 2008×64 on Server 2008×64, (named instance) and I continually get the error 26. Have checked all the issues you list. When will the fix for Server 2008 x64 – Clustered SQL 2008 be available?

    Thanks,

  29. John Teutsch says:

    Nevermind. Firewall was "on", albeit showed up as red in control panel because wasn’t configd with all of the recommened settings.

  30. Lakshmi says:

    I have been able to connect to Sql Express using the Data connection Wizard.But when I connect using code I have an error that says that remote connection is not possible error 40.In spite of doing all possible changes to the settings of SQL Config manager and firewall. Please help me fix this problem.Thanking you in advance.

  31. What’s the connection string in your code?

    Do you run your code and Data connection Wizard under different account? Can you make sure the account under which you run your code has permission to at least open a fileshare to the target machine(if not local)?

    Thanks,

    Xinwei

  32. Miles says:

    we installed 2 virtual server on a cluster, each with 1 named instance but no DEFAULT instance. we set the port for both instances to 1433, do we still have to specify "server=ip,1433" in the connect string?

  33. If you have a clustered SQL Server 2000 or SQL Server 2005 you might have the following error message:

  34. Pieter Kops says:

    We had similar issues.

    The servers on the LAN side worked fine. The one in the DMZ could not connect to the SQL server. We could ping it and browse.

    The reason it didn’t work in our network was this.

    The SQL browser listened on IP adres 10.0.0.44 (the IP address of the virtual node) and replied using the IP address of the physical node.

    Our Firewall blocked the packet because it was no reply to a request and therfore had no business getting into the DMZ.

    After creating a policy in the Firewall allowing the ip address to access the DMZ it all worked fine.

  35. Ben Miller says:

    There have been a couple of issues that keep pestering the SQL Server community for those that use Vista

  36. Spike Robinson says:

    We are about to move a very large number of databases from SQL2000 and SQL2005, on to a SQL2005 Cluster. As I am reading this article, named instance resolution on SQL2005 Clusters is going to break with Vista, and also break with any app or device that enforces strict UDP i.e. checks that the IP address of the reply matches the IP address of the original destination. This is an important test to apply because it screens off a lot of serious UDP attacks, including attacks that target SQL Server specifically.

    Xinwei, you are saying the problem originates in the UDP protocol but is it not the case that this could be fixed in the SQL Browser Service? Other services can listen on specific IPs and ports, is it that expensive to have the *option* to configure SQL Browser the same way?

    I also have another suggestion that you can implement which is much less expensive and makes the Browser service compliant with correct UDP checks. Have the Browser Service inspect the UDP packet header and check the destination address. If the destination address is an available direct attached interface and routable to the sender, have the Browser Service send the response packet with an origin address of this interface, via the interface. That will then pass strict UDP checking and contribute to everyone’s security.

    As a bonus you could also have the Browser (optionally) discard packets that had a (forged) origin on a local interface or a (forged) destination that is not a local interface.

    We really need this fixed on 2005, not just 2008. To be honest we are avoiding Vista as it’s a nightmare. But we still need our SQL2005 Cluster to work properly. Microsoft should make sure that all its supported products comply with security best practices. Sending UDP replies, with a different origin than they were originally sent to, does not comply.

    I hope you will be able to do something. Thanks very much to Xinwei and other contributors for all the excellent information here, it has helped us understand this problem.

  37. MB says:

    Please let me know in case there is any solution.

  38. I have 2-node SQL Server 2005 Cluster which configured as Active/Passive mode, let say A node and P node. I already install 1 CRM instance on this cluster before. Now I wanna to install a second 2-node cluster on these…

  39. slipknot says:

    Below is the error that SSIS is throwing when trying to connect to a NAMED SSAS instance on a windows CLUSTER

    A connection cannot be made to redirector. Ensure that ‘SQL Browser’ service is running.

  40. LC says:

    The issue still isn’t fixed when running Windows 2008 Ent Server w/SP2 and SQL 2008 Ent w/SP1 and CU1.  We’re running sql with 2 VLANs (1 for Production and 1 for Backups) and we’re still getting the infamous "The SQLBrowser service was unable to process a client request." error.  It’s crippling our website and causing a lot of pain.  You mention adding the port to our connection string as a workaround which may help, but it doesn’t help SQL Server Agent.  SQL Server Agent jobs (mostly T-Log backups) fail constantly with the SNAC error above.  I’m guessing it’s b/c they log in via one VIP then write the backups down the 2nd VIP?    

    I should note we recently upgraded the servers in-place from SQL 2005 w/SP2 and CU9 (OS stayed the same).  We never experienced this issue on SQL 2005 which is ironic b/c it seems it’s been a chronic problem since the Browser’s inception.  Now when it’s supposed to be fixed we finally get burned.  

    Please don’t let this drag out like the security cache fix for SQL 2005….took multiple tries/hotfixes to finally resolve it.  

  41. Keith says:

    We ran into this as well.  We solved the problem by adding a firewall exception rule to the Vista Client box that allowed all traffic / all ports between the client PC and the Server IP Address.  We figured if the SQL Cluster got hacked we would have bigger problems than it attacking the clients.

  42. Rx says:

    Linked Server from SQL Server 2005 (on cluster) and to SQL Server (web edition) 2008 – not on cluster.

    SQL 2008 has a serverdbInstanceName using SQL Server security (username & password) for a WebData database.

    I am trying enterprise manager from 2005 to connect to the 2005 db – and get SQL Network Interfaces, error: 28 – server doesn’t support requested protocol

    Do I need to turn on a port?

    Is there a sequesnce to connect?

    e.g. 10.1.2.1dbInstance  

  43. Yogesh Patil says:

    I have strange issue where in I am unable to connect to SQL server over local LAN. However I do not have any issue

    a) if RDP to other server and try to connect from it. b) if I am on VPN then I do not have any issue.

    c) if I try to connect <IPAddress>,<Port> then I am able to connect over local LAN through desktop.

    Note:- IP Address of server has been changed recently and person who is in same subnet as me is able to connect to server without any issue.

    Any help on it would be appreciated.

  44. Hi Yogesh,

     Rather than leaving comments on this blog with questions, please post questions on the MSDN SQL Server Data Access Forum: http://social.msdn.microsoft.com/Forums/en-US/sqldataaccess/threads. When you start a thread there, please include the full, exact error message that appears when you fail to connect.

  45. pp-roni says:

    Hi i have the same issue sometime ago and i just start Sql Server Browser in services

    hope it works for anotherones of you

  46. Dee says:

    Hi,

    My installattion is on my Local Machine.

    I reinstalled SQL Server 2005 and am unable to connect to the server.

    I am using Windows authentication Mode. My computer Name is NINJA.

    So I used the server name as NINJASQLEXPRESS.

    It is giving Error 26.

    TITLE: Connect to Server

  47. Michael says:

    The problem for us was the binding order on the NIC’s as we had recently enabled new ones. Correct the binding order in network connections then reboot.

  48. jaedah says:

    hi! i have just installed SQL Server 2005 Management Studio. When I open the program, I am first prompted to type the server name, along with the authentication and the database name. I use my PC name as the server name. I do not know what instance name to put. Does anyone here know how I could connect to server so I can create a database? Help please. Thanks.

  49. It is a very interested article. Thanks.

    Would not be an easier solution to add an alias on the client side so Connection Strings do not change and not need to specify IP address?

    Your comments are strongly appreciated.

  50. Xinwei Hong says:

    Noravia,

    Using alias could be a workaround. The drawback of alias is that it has to be defined on all client machines(if you have multiple clients) and you need to update it when the server side configuration changes. Also, it’s easy to forget to delete the alias when the server is uninstalled.

  51. Phil Davenport says:

    On one PC I could not find any firewall software running and I had to flatten and re-load the operating system.  This fixed my problem.

    On another PC I was able to alter the firewall software to allow UDP on all ports both incoming and outgoing for my application.  This solved the same error message 26 on that PC.

    I do not know whether on a connection string it is possible to use ODBC.  I only had the Error 26 when connecting from Visual Studio and C# applications.  And only on specific PCs.  MS Access linked tables always worked from all PCs to the SQL Cluster.  Also SQL Server Management Studio was always able to connect without altering the firewall settings.  If it is possible to use ODBC in a visual studio application connection string, please let me know.

    THANK YOU.

  52. Jenie Bui says:

    Thank you.

    I have the same issue when connect SQL 2005 name instance from SQL 2008. Using the IP address solve the issue.

    Great post.

    Jenie

  53. prath says:

    Iam using EnumAvailableServers(Boolean) API of SMO to enumerate sql instances but it is returning zero list sql 2008 sp1 cluster on windows 2008 sp2.  But this API is working absolutely fine for non cluster sql 2008 sp1 on win2008 sp2…

    What happened to cluster?????? Is this bug didnt fix in cluster???

  54. Xinwei Hong says:

    Prath,

    We are not aware of such an issue, and I don’t expect such an issue. But we will try repro locally to see if that’s true. Also, please note that the enumeration is not guaranteed to return all servers in the network.

    Thanks,

    Xinwei

  55. Pradeep says:

    Microsoft SQL Server 2005 – 9.00.4035.00 (X64) Enterprise Edition (64-bit)

    Windows NT 5.2 (Build 3790: Service Pack 2)

    2 Node Cluster which has 2 Instances of SQL Server 2005 AND 2 Instance of SQL Server 2008

    BROWSER.EXE is 2007.100.2531.0

    When instance is failed over to 1 node port resolution fails, I am able to connect if i specify the

    port number in the connection string. When the instances are on the other node it works fine.

    In the Application log i see this error : The SQLBrowser service was unable to process a client request

    When we start browser service from console we get the below output

    SQLBrowser: starting up in console mode

    SQLBrowser: starting up SSRP redirection service

    SQLBrowser is successfully listening on 0.0.0.0[1434]

    [5172]: Waiting for next request…

    [1752]: Waiting for next request…

    [6096]: Waiting for next request…

    [5792]: Waiting for next request…

    [5172]: Received request…

    [1752]: Received request…

    [5172]: Waiting for next request…

    [1752]: Waiting for next request…

    SQLBrowser: starting up OLAP redirection service

    [5172]: Received request…

    CLNT_UCAST_INST w/refresh from 192.168.10.11[3370]

    CLNT_UCAST_INST from 192.168.10.75[3370]

    [5172]: Waiting for next request…

    [1752]: Received request…

    CLNT_UCAST_INST w/refresh from 192.168.10.11[3371]

    CLNT_UCAST_INST from 192.168.10.11[3371]

    [1752]: Waiting for next request…

    Windows Firewall and Antivirus has been stopped and disabled. Restarting browser did not help.

    Any idea if i am hitting the same issue that has been explained above. On the other node even

    if windows firewall and antivirus is running i dont face this issue.

  56. Tyge says:

    Thanks for the information in this Blog. It has allready helped.

    Description of our enviroment.

    A central phone provider has 300 customers that will recieve phone traffic, in a closed MPLS enviroment. But some of the service is User management that is done on a central MS-SQL cluster.

    The cluster is behind a firewall. The firewall will make NAT of the Cluster VIP IP , and make it into a RIPE addres. The customer will use a Computer, and access the application with a SQL client connection. The client computer has it’s IP address changed in the Customers firewall. The traffic is between to different domains, with no trust.

    When reading this blog, we made a standalone SQL server, with a default DB installation. And it works. Thanks 🙂

    NOW – I need to make a cluster SQL database due to high availibility SLA. The SQL Cluster database need to have not one but 3 different DB installed. How the hell do I do this?

    Suggestions accepted with smiles.

  57. Xinwei Hong says:

    Tyge,

    Your configuration looks complicated. But, if standalone SQL Server works, cluster should also works. You can use IP address directly to isolate if it’s a SQL Browser related issue. Please post question in our forum:

    http://social.msdn.microsoft.com/forums/en-US/sqldataaccess/threads/

    Thanks.

  58. Robert Coupee says:

    Does this problem occur on when conecting from a client running Windows 2008 R2 to a Named Instance of SQL Server 2008 SP1 running on a Windows 2008 R2 Cluster? If so what is the fix?

  59. Namrata C says:

    Might be it's a same old question for you but I can't understand where to start resolving this issue in my WPF application.

  60. Tim says:

    If you use version 2008 SQLEXPRESS the port ist NOT the standard port 1433.

    If you use a port that is not 1433 you have to start SQL Browser service (manually) to let your sql server to be found in the network.

  61. John W says:

    Microsoft SQL Server 2005 – 9.00.4035.00 (X64) Enterprise Edition (64-bit)

    Windows NT 5.2 (Build 3790: Service Pack 2)

    2 Node Cluster which has 2 Instances of SQL Server 2005 AND 2 Instance of SQL Server 2008

    BROWSER.EXE is 2007.100.2531.0

    When instance is failed over to 1 node port resolution fails, I am able to connect if i specify the

    port number in the connection string. When the instances are on the other node it works fine.

    In the Application log i see this error : The SQLBrowser service was unable to process a client request

    When we start browser service from console we get the below output

    SQLBrowser: starting up in console mode

    SQLBrowser: starting up SSRP redirection service

    SQLBrowser is successfully listening on 0.0.0.0[1434]

    [5172]: Waiting for next request…

    [1752]: Waiting for next request…

    [6096]: Waiting for next request…

    [5792]: Waiting for next request…

    [5172]: Received request…

    [1752]: Received request…

    [5172]: Waiting for next request…

    [1752]: Waiting for next request…

    SQLBrowser: starting up OLAP redirection service

    [5172]: Received request…

    CLNT_UCAST_INST w/refresh from 192.168.10.11[3370]

    CLNT_UCAST_INST from 192.168.10.75[3370]

    [5172]: Waiting for next request…

    [1752]: Received request…

    CLNT_UCAST_INST w/refresh from 192.168.10.11[3371]

    CLNT_UCAST_INST from 192.168.10.11[3371]

    [1752]: Waiting for next request…

    Windows Firewall and Antivirus has been stopped and disabled. Restarting browser did not help.

    Any idea if i am hitting the same issue that has been explained above. On the other node even

    if windows firewall and antivirus is running i dont face this issue.

  62. ASundstrom says:

    I found this error when using SQL Management Studio 2008 and trying to connect to an SQL 2000 DB Instance on a SQL Cluster.  If I use SQL Management Studio 2000 it works fine.

  63. mickey-liu says:

    I have a weird phenomenon

    our prod env:

    os:windows 2008 sp1    cluster: sql 2005 cluster (instacne A1)

    when connect to A1 that's ok, and the firewall is open

    the test env:

    os:windows 2008 R2   cluster: sql 2005 cluster (instacne A1)

    when connect to A1 that's failed,  any relate sql port , we opened, but not work, only close the firewall it will be ok through the instance name, and our application is a web application, can not add the app to firewall exception,and our customer did not want to add the port after the instance name , is there any other idea?