Issue with hostname resolution when configure NetWeaver provider on Azure Monitoring

Question

Hello Experts,

I have a problem with the DNS resolution when configuring the Azure Netweaver Provider for our SAP systems. I believed all the configuration were corrected, the host entries were generated using auto-generate hostfile and the network validation was successfull as well.

However, I still face below error.

I also tried to SSH to function app for checking the DNS resolution and it works fine as well.
Did anyone have the same situation before? If yes, could you please tell me where I can check the root cause of it? Thank you so much in advance!

Answer 1

Hi Cuong Nguyen,

I would say its looks like a classic situation where DNS appears to work from your test but does not work in the context in which Azure Monitor actually connects to SAP. NameResolutionFailure in Azure Monitor for SAP almost always means the service itself cannot resolve the hostname the same way your SSH session does. The fact that tcpping works from Kudu does not guarantee that the same resolver is used by the provider at runtime. The hostfile entries you generate apply to the SAP central server, not to the Function App or the Kudu container. If the SAP application server inside its network cannot resolve the same FQDN, Azure Monitor will return a temporary failure in name resolution. A common issue is that short names are defined in the hostfile while the provider connects using FQDN, or the other way around, and even a small mismatch in the hostname can trigger the error. You should verify that the hostname specified in the Application server field exactly matches the name that actually resolves, check for split DNS behaviour, and confirm there are no hidden characters or formatting issues in the hostfile mappings. A successful network validation only confirms TCP connectivity and does not guarantee correct DNS resolution behaviour. It is also advisable to enable diagnostic logs for Azure Monitor for SAP solutions and identify which hostname is failing to resolve, as in most cases the root cause is either an FQDN mismatch or a DNS configuration issue on the SAP side.

LMK

rgds,

Alex

Answer 2

Hello Cuong Nguyen, 

You are configuring the SAP NetWeaver provider in Azure Monitor for SAP solutions (AMS). Even though host entries were auto-generated, Network validation passed, and DNS resolution works when you SSH into the Azure Function App,

the provider creation/update fails with the error: Provider settings validation operation has failed with code "NameResolutionFailure" This indicates a DNS resolution failure during provider validation, not during manual testing

This happens due to the following reasons:

• Provider validation runs from Azure Functions, not from your SAP VM or SSH session
• Host file entries are ignored during provider validation
• If custom DNS servers are configured on the VNet and they do not forward queries to Azure DNS, Azure-managed services fail DNS resolution
• If SAP hostnames are resolved using Private DNS zones, those zones must be linked to the AMS subnet VNet, otherwise name resolution fails

Microsoft explicitly documents that Azure Monitor for SAP solutions requires correct VNet DNS configuration, and missing Azure DNS forwarding is a common cause of such failures. This exact symptom has also been reported by other customers with the same error code.

Verify VNet DNS configuration:

• Go to Virtual Network > DNS servers
• If Custom DNS is configured:
  • Ensure your DNS servers forward unresolved queries to 168.63.129.16
  • This is mandatory for Azure-managed services

Set up a network for Azure Monitor for SAP solutions | Microsoft Learn

Validate DNS from the AMS subnet

• Do not rely on SSH into the Function App
• Instead:
  • Use Azure Network Watcher > Connection troubleshoots, or
  • Temporarily deploy a test VM in the same subnet used by AMS
    • Test FQDN resolution of SAP hosts from there

Check Private DNS zone linkage

• If SAP hostnames are in Private DNS zones:
  • Ensure those zones are linked to the VNet where the AMS Function App subnet exists
  • Without this, AMS validation cannot resolve hostnames

Set up a network for Azure Monitor for SAP solutions | Microsoft Learn

Ensure FQDN is used: Configure the NetWeaver provider using fully qualified domain names. Short hostnames may work on VMs but fail during provider validation

Hope this helps! If you encounter any issues, please reach out to us. Thanks.