从 .NET 访问 DB Core Web API 部署为 Azure Web App

Question

Problem :

We have a .NET Core Web API that we have just deployed as an Azure Web App. Testing locally everything works fine, however we are unable to connect to our DB from the deployed API in Azure.

From Application Insights I can see we are getting the following error:

Microsoft.Data.SqlClient.SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible.

Our setup :

We have our connection string included in appsettings.json

"ConnectionStrings": {
    "DefaultConnection": "Data Source=<source>.com,<port>;Initial Catalog=<db>;User ID=<username>;Password=<password>;MultipleActiveResultSets=False;Encrypt=True;TrustServerCertificate=True;Connection Timeout=30;"
},

We know our API is using this connections string because we can see in Application Insights that there is a timeout connecting to the db specified in that exact connection string.

We do not have access to DB configuration as we have read only access granted to us from a third party. We can connect via SSMS/Azure Data Studio and when testing our Web API locally (which makes us think the connection string is correct).

Other Posts we have Referenced :

• Connection String in Azure Web App Configuration - I have tried including and not including our connection string from the Azure App Service Configuration - neither changed that we got a timeout and subsequent 500 error.
• Include Connection String in appsettings.json - We have our connection string included in appsettings.json and testing locally, we can connect to the db without issue.
• Improperly Formatted Connection String - The connection string works when testing locally, so we do not believe it to be an issue with the formatting of the connection string. Additionally, because Application Insights says that there is a timeout connecting to the DB specified in the connection string, it appears to be using the connection string we are providing.

Any ideas as to what might be going on here and how we can connect to the DB would be greatly appreciated.

Answer 1

In this case, we needed to request that the third party whitelist our Azure Web Apps Outbound IP's.

Your Azure Web App Outbound IP's can be located in a number of ways.

Via Azure Portal

Web Apps > Your Web App > Under "Settings" go to Networking > Outbound Addresses

Via Azure CLI

az webapp show -n yourwebappname -g yourresoucegroup --query "outboundIpAddresses"