NAT Gateway provides 64,512 SNAT ports per public IP address and supports up to 16 public IP addresses. Monitor "Total SNAT connection count" metric to determine if you're nearing the connection limit of NAT gateway. You can scale the NAT gateway by adding more public IP addresses.
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Configure monitoring and alerting for NAT gateway
Impact:HighCategory:Monitoring and AlertingPG Verified:Preview
APRL GUID:babf75d6-6407-4d90-b01e-5a1768e621f5
Description:
Use Network Insights for monitoring and alerting on your NAT gateway.Use Total SNAT connection count metric to determine if you're nearing the connection limit of NAT gateway. Set alerts based on Azure Monitor Baseline Alerts (AMBA) thresholds for NAT Gateway
A zonal promise for zone isolation scenarios exists when a virtual machine instance using a NAT gateway resource is in the same zone as the NAT gateway resource and its public IP addresses. The pattern you want to use for zone isolation is creating a "zonal stack" per availability zone.