---
title: "Best Practices, Limitations, and Known Issues of Azure DNS Integration"
canonical: "https://docs.infoblox.com/space/vniosazure/686162022/Best%20Practices%2C%20Limitations%2C%20and%20Known%20Issues%20of%20Azure%20DNS%20Integration"
format: markdown
---
Some of the best practices you could use when using the Azure DNS integration feature introduced in NIOS 9.0.4, the limitations, and the known issues of this feature are discussed in this topic.

## Best Practices

- Ensure that the time on the NIOS or vNIOS appliance is synchronized with the actual time so that Azure DNS synchronization functions properly.
- Depending on the number of hosted zones and resource records, the synchronization of Azure DNS data could consume a significant amount of memory and database capacity.
  - When you configure the Grid member to pull Azure DNS data, ensure that the Grid member has sufficient capacity to handle a bulk import of DNS data.
  - Infoblox suggests that you select a member that is not running other services and can handle the synchronization load for this feature.
- To reduce unnecessary data synchronization and to ensure optimal performance in your Grid, use filters to specify the hosted zones that you want to import into the NIOS database when you configure sync tasks. For information about how to configure sync tasks, see *Managing Azure DNS Sync Groups*.
- If you install a hotfix for the Cloud Sync service, you must manually stop the service and restart it for the hotfix to take effect. For steps, see the *[Prerequisites for Azure DNS Integration](https://infoblox-docs.atlassian.net/wiki/spaces/vniosazure/pages/686063963)* topic.
- Azure supports multiple values for a resource record set. After data synchronization, NIOS creates multiple records (one for each value that is specified in Azure).

## Limitations

- NIOS does not support the use of special characters \ or " in the name of a DNS sync task. A DNS sync task will fail if you use any of the unsupported characters in its name.
- vNIOS for Azure does not synchronize Apex DNS records (Azure @ records) to the NIOS database as they do not contain any DNS data.
- vNIOS for Azure does not support synchronizing DNS resources created using the **Front Door and CDN profiles** option that are created with the Standard offering (pricing tier - Standard) of Azure. To synchronize such resources, you must create them with the Classic offering of Azure.
- vNIOS for Azure does not support synchronization of an AAAA alias record to NIOS, if the record is created with **Azure resource** selected as **Public IP address**, which was created with its **IP Version** as **IPv6** and **SKU** as **Basic**. To synchronize such a record, you must set the **SKU** of the public IP address as **Standard**.
- In NIOS, if you modify DNS records synchronized from Azure DNS, the changes will be overwritten in subsequent synchronization. However, DNS records that are manually created in zones synchronized from Azure DNS are not removed in subsequent synchronization.
- NIOS does not synchronize Azure DNS data to a network view whose authority is delegated to another Grid member. When you configure a sync group, ensure that you select a network view that is not delegated.
- Azure DNS zones and records cannot be synchronized to NIOS database when a zone is signed because signing a zone encrypts the records.
- NIOS does not import SOA records for hosted zones. When you configure a primary and secondary name servers to serve the hosted zones, NIOS creates the NS records and use the default SOA records for these zones.
- To use the Azure DNS integration feature on a vNIOS instance deployed with the NIOS 9.0.4** **resizable image, you must ensure that the vNIOS instance is allocated with a minimum disk size of 250 GB or more. If not, the Cloud DNS Sync service will not work properly.
- When running a scheduled upgrade from NIOS 8.6.x to 9.0.4 on a Grid that has members assigned to Azure sync groups, the Cloud Sync service on such members keeps restarting as the RabbitMQ password will not yet be updated. To update the password, wait for the upgrade to complete, and then run the `set update_rabbitmq_password` command on the Grid Master in the maintenance window.
- Querying a CNAME ALIAS record synchronized through Azure DNS returns the TTL value defined in the Grid DNS Properties instead of the value defined in its parent CNAME record.
- NIOS does not support the following Azure DNS data:
  - Duplicate records (or records using the same name and same record type) in a hosted zone using "non-simple" routing policies.
  - Duplicate Azure DNS public hosted zones.
  - "Tags" in Azure DNS resources (similar to extensible attributes in NIOS).
- A record name must only contain letters, numbers, underscores, and/or dashes. For more information, refer to the Azure documentation.
- For NS records synchronized through DNS synchronization, values are not populated in extensible attributes related columns such as Creation Time and Cloud Shared in the **Data Management** > **DNS** > **Zones** table because NIOS considers NS records as system records and therefore it cannot associate the extensible attribute values with the records.

## Known Issues

- NIOS does not support CAA alias records from Azure DNS.
- SPF ALIAS records synchronized to NIOS from Azure DNS cannot be queried because NIOS does not support the SPF record type.
- The **Allow Deep Packet Inspection** option configured in NIOS for the proxy server to run a deep-packet inspection while fetching the DNS data from Azure for a DNS sync task, is currently not supported.
- In an HA setup, if the Cloud Network Automation license is not installed in any of the two nodes, the HA status will not display a missing license message.
- Multi-subscription DNS synchronization may cause a high CPU usage for some duration when synchronizing data from large number of subscriptions. The usage drops to normal levels after the CPU intensive processes are completed.
- If a DNS sync task is synchronizing large amount of data, some data may not synchronize due to the load on the server. Subsequent runs of the same task will eventually ensure that the synchronized data is consistent with the data in the Azure cloud.
- If you have configured a rotation of your credentials or access keys, some of the DNS synchronization tasks may fail with an error.
- Infoblox recommends that you do not start the Cloud Sync service for an offline member although the **Manage Member Services** option allows you to start the service for an offline member.
- The Global Search function in Infoblox NIOS Grid Manager does not support filtering of data by using the Subscription ID filter. You may use the **Quick Filter** option in the **Zones** > *DNS_view* screen.
- If the “error:couldn't create memory pool" error is displayed during an vDiscovery job, it means that a restart of services has not been performed by clicking Restart Services on the Toolbar when the Restart Banner is displayed on top of Grid Manger. If a service restart is delayed for any reason, the error will not be resolved even after the restart. To resolve the error, run the set purge_restart_objects **Admin** **CLI command.**