Opening Ports

  • Did somebody have problems with ports?

    I have web application on the external server on DMZ and database is in the internal network and application suppose to connect to the database. I get an error that SQL server doesn't allow remote connections. This is not true because SQL Server settings say "Allow remote connections". User name/password is also correct. I think some ports should be open to allow those two servers to communicate to each other. Can somebody tell me what should be open, where (on both servers?), how to do it or point me to some resources?

    Thanks,

    Vika

  • Do you have TCP connections enabled for the server (use Surface Area Configuration to check/set this)

    Regards,

    Andras


    Andras Belokosztolszki, MCPD, PhD
    GoldenGate Software

  • Make sure you're using TCP/IP. Named Pipes usually is only for local connections.

  • Do you mean I should check if TCP/IP is enabled in SQL Server Surface Area Configuration for Services and Connections?

  • Yes. This must be enabled if you want to connect to the SQL Server via TCP/IP. As Steve mentioned, named pipes can be used for local connections only.

    Andras


    Andras Belokosztolszki, MCPD, PhD
    GoldenGate Software

  • Oh well, didn't work. In the surface area configuration is set to "Using TCP/IP only", so it's OK here. Maybe ports should be opened  in the firewall somehow or something.

  • SQL Server listens on TCP port 1433 (the default instance). Try connecting to this port from the remote machine using telnet or something similar. Also, if you have a named instance, it gets a random port. In order to connect to such a named instance, port 1434 must be open for UDP. Alternatively, you can fix the port for the named instance.

    Regards,

    Andras


    Andras Belokosztolszki, MCPD, PhD
    GoldenGate Software

  • When I type "telnet ip_address 1433", it connects and i see empty screen.

    When I type "telnet ip_address 1434", I get "Could not open connection to the host on port 1434 connection failed". What is UDP, named instance, how to open port 1434 or fix the port for the named instance?

  • The fact that you can connect to 1433 is a good sign. This should mean that SQL Server is listening on that port, and that you can connect to it. A named instance is generally used if you have more than one SQL Server installed on a machine. Do you have more than one SQL Server on this machine?

    Do you have any SQL Server client tools installed on the machine in the DMZ? Have you tried to connect to the server using osql or Management Studio? If so, could you post the exect error message please?

    Regards,

    Andras


    Andras Belokosztolszki, MCPD, PhD
    GoldenGate Software

  • I checked database server from my local machine using telnet and it connects to port 1433. I tried to connect from  application server on DMZ and it cannot  open that port. So port 1433 is opened on SQL Server, but something on DMZ prevents connection. And there is only one SQL server over there, no named instances.

  • I'm glad that you have isolated the problem,

    Andras


    Andras Belokosztolszki, MCPD, PhD
    GoldenGate Software

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