SQL Server communication over subnets

  • Hi Folks,

    OK, the problem is that I am trying to configure two SQL Server 2005 machines to communiacte over two subnets so obviously a router is sitting in the middle. When I run osql -L there are no SQL Servers in the second subnet listed and so my first thought was that traffic was being blocked at the router. Unfortunately it is not that simple!

    I have done the following on both ends of the proposed connection:

    1. I have used the Configuration manager to ensure that TCP/IP is enabled

    2. In the Surface Area Configuration Manager I have ensured that Remote Conections are allowed.

    3. At the instance level in the Server Properties under Connections, "Allow Remote Connections to this Server" has been checked.

    I can PING the target router to see that it is alive but SQL Server itself cannot see the other instance.

    I would be grateful for any help you can offer!

    Regards,

    Kev

  • Could it be that SQL Browser services needs to be active so that oSQL will see servers. Also you may want to check if your firewall settings have blocked UDP 1434 since that's used by SQL Browser?

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  • Hi!

    Thanks for the prompt answer.

    I forgot to mention that! The SQL Server Browser is active on both ends. Does the browser not use 1433 for the default instance and then 1434+ for the remaining named instances?

    Regards

    Kev

  • The SQL Browser Service uses UDP 1434. This is commonly blocked at firewalls. Why do you need to discover the server using Browser? Can you connect directly to the FQDN or IP Address?

  • The Browser is the most convenient way to connect to each of the servers. Using the "Connect to" dialog box enables our developers and testers to connect to instances and databases without the additional hassle (and some of these people look at it as being "hassle"!) of remembering an IP Address.

    The second reason the Browser is helpful for us is the use of the "osql -L" command that allows us to inventory the SQL Server landscape from the command line although at the moment this command cannot cross the boundary between the subnets.

    The third reason is that our Reporting and Analysis Services-based servers have the business requirement that they should be accessible using Browser services, a point I have argued but stands firm.

    A connection using an IP Address also does not work, something that is more than a little irritating and which also makes me think that perhaps an access list is in place at the network boundary. The problem is that our Infrastructure Team assure me that no firewall exists between the subnets and that router-based ACLs are also not active.

    The problem is a confusing me...........

  • Can you telnet to the SQL Server port over the router? Don't assume it is 1433. Check using SQL Server Configuration Manager. Beyond this, I would use WireShark to see trafffic to/from the boxes.

  • Agree with Randy they potentially could be on non default port for your SQL Servers. (e.g. named instance possibly)

    Have you tried using a tool to check the ports?

    Microsoft has a tool that allows you to specify specific IP address and port.

    http://www.microsoft.com/en-us/download/details.aspx?id=17148

    Hope that works? Then you can confirm if the port is blocked maybe?

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