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Problem connecting to SQL Server over firewall

  • August 13, 2010 at 12:28 pm

    #222587

    Hello!

    I am troubleshooting connectivity from client computer to SQL Server 2008 named instance. We have opened 1433 and 1434 ports to allow connectivity. I am able to connect using <SQLServerName>\<InstanceName>,<PortNumber> syntax. But I would like to connect without specifying port number. SQL Server Browser service is running on SQL Server. Also, IPall settings in TCP/IP protocol is configured to use dynamic port in question.

    I am not sure if there any other ports that I have to open to allow connection without specifying port nunber. I am able to connect using <SQLServerName>\<InstanceName> from clients that don't go through firewall (for exmaple, inside SQL Server network). That makes me think this is firewall restrictions.

    Any help is greatly appreciated.

    Igor

  • August 13, 2010 at 1:44 pm

    #1206911

    servername\instancename is resolved by the WINS service and the SQL browser. that's not exposed to the WAN, just TCP/IP addresses.

    since you are using a firewall to the outside world, you have to take the port into consideration to connect.

    also, to avoid being hammered by kiddie scripts from china nad russia, you should never open default ports 1433/1434. switch them to something else with the configuration manager or port forwarding ont he firewall...you know, incoming 41433 is forwarded to intenral machine 192.168.1.200 port 1433

    so for example, if your external IP was 72.30.2.43 [yahoo.com actually] , then the client needs to use 127.0.0.1[comma][port] to connect : 72.30.2.43 ,41433 for example.

    Lowell

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  • August 13, 2010 at 3:09 pm

    #1206944

    Lowell,

    Sorry, I didn't make myself clear. Client computers are not in the 'outside world'. They are within different subnet. Our network guys configured traffic so that it has to go through the firewall though.

    I actually found an article that might shed some light: http://support.microsoft.com/kb/318432/

    Thanks,

    Igor

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