Blue Matador automatically monitors the blocked_by_firewall and connection_failed metrics for Azure SQL Databases to warn you when connections to your database are not succeeding.
Blocked Connections
Blocked connections are likely caused by firewall settings on your SQL server or database. Firewall settings are configured in two places: the SQL Server configuration can be used to create firewall rules for all databases in the server, and each server can also define its own firewall rules. This blog has detailed steps on viewing and modifying firewall rules in both locations.
Failed Connections
Failed connections are connections that were not blocked by a firewall rule but were still unsuccessful. Failed connections can either be transient or persistent depending on their cause.
For transient connection issues, Microsoft Azure recommends the following troubleshooting steps:
- Check the Azure Status Dashboard for any issues with Azure SQL
- Review the Transient errors best practices to ensure your application is properly retrying connections
- If your database is near its resource limits this may be the root cause of transient connection issues
- If connection issues continue or happen several times throughout the day, create a support ticket.
Persistent connection issues are likely an issue with one of the following:
- A firewall between the client and the SQL database
- Network configuration on the client, such as an invalid proxy configuration
- A misconfigured client: invalid connection string, ports, or low connection timeouts.
