DNS questions to basic service like mongodb and influxdb on azure app functions

Question

We are experiencing frequent and intermittent DNS resolution failures from an Azure Function App hosted in France Central, when connecting to standard external services such as MongoDB and InfluxDB. We do not experience dns issues from other services which access MongoDB or InfluxDB.

This is impacting production workloads and appears to be infrastructure-related rather than application-level, as retries typically succeed without code changes.

Is there a known ongoing issue affecting DNS resolution or outbound connectivity in France Central? Could this be related to incident 3SQT-7RG, or is there another advisory we should be aware of?

What is the recommended escalation path to investigate this further?

Answer 1

Hi ,

Thanks for reaching out to Microsoft Q&A.

1. Yes, intermittent DNS resolution failures from azfunc app are a known failure mode during and shortly after app service platform maintenance in a region.
2. This can be related to incident 3SQT-7RG, even if it is marked resolved. DNS instability often lingers due to worker reallocation, SNAT pressure, or internal DNS cache resets.
3. There is no separate public advisory currently specific to DNS in France Central, but this pattern is consistent with prior app service infra issues.

Why this points to platform, not your code

• Only Azure Functions in France Central are affected.
• Other services reaching MongoDB and InfluxDB are fine.
• Retries succeed without changes.
• Errors show 127.0.0.11:53 timeouts, which is App Service internal DNS.

this is almost certainly Azure App Service infrastructure, not MongoDB, InfluxDB, or your code. Escalate via support with the incident reference and push for a stamp level investigation.

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