Troubleshoot Intermittent DNS Resolution Failures on a VA Deployed on Azure
If you have deployed the VA on Azure as a stand-alone virtual machine (VM) without a public IP address, you might experience intermittent DNS resolution issues when heavy DNS traffic is directed at the VA. This is due to SNAT port exhaustion on virtual machines deployed to Azure (such as the VA) because Azure only pre-allocates 1024 UDP ports for standalone VMs without a public IP address. To address this issue, you may either need to assign a public IP to each VA or deploy VAs behind a public Standard Load Balancer in Azure.
Note: If you are assigning a public IP to a VA, make sure that there are no inbound port rules for this VA that allow inbound access from the internet.