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Azure suddenly cannot connect to remote db (which is online) RRS feed

  • Question

  • User-1655763558 posted

    I have an asp.net framework mvc web app deployed to Azure that connects to a remote (non-Azure) SQL Server db. The db allows remote connections. This has worked fine for months but suddenly with no changes made the web app throws this error whenever it tries to connect:

    System.Data.SqlClient.SqlException: A transport-level error has occurred when receiving results from the server. (provider: Session Provider, error: 19 - Physical connection is not usable)

    I have done the following:

    1. Verified the db is online and is accessible via SSMS
    2. Run a local copy of the web app through VS / IIS Express to ensure it can connect to the db
    3. Deployed the web app to another non-Azure web server and had it connect to the db
    4. Restarted the web app on Azure

    Why would Azure suddenly be unable to connect when the database is clearly online and accessible via these other channels?  How can I fix this?

    Friday, November 1, 2019 1:19 AM

Answers

  • User-1655763558 posted

    Thanks for the reply.  The issue was the host of the SQL Server was employing some new anti-DDOS technology and that was blocking some - not all - remote connections.  They have resolved the problem.

    • Marked as answer by Anonymous Thursday, October 7, 2021 12:00 AM
    Friday, November 1, 2019 3:49 PM

All replies

  • User61956409 posted

    Hi,

    • Run a local copy of the web app through VS / IIS Express to ensure it can connect to the db
    • Deployed the web app to another non-Azure web server and had it connect to the db

    I'd like to confirm these information with you:

    • Can you connect to the db from your app locally?
    • If you deploy the app to another Azure web site/Azure hosting server, can it connect to the db as expected?
    • If any updates or new setting did on your SQL Server?

    With Regards,

    Fei Han

    Friday, November 1, 2019 8:18 AM
  • User-1655763558 posted

    Thanks for the reply.  The issue was the host of the SQL Server was employing some new anti-DDOS technology and that was blocking some - not all - remote connections.  They have resolved the problem.

    • Marked as answer by Anonymous Thursday, October 7, 2021 12:00 AM
    Friday, November 1, 2019 3:49 PM