Azure Firewall NAT Behaviors

Hey SBrickeyRCS , all outbound virtual network traffic IP addresses are translated to the Azure Firewall public IP. You can find that information here: Azure Firewall Standard features | Microsoft Learn. So any Public IP that is associated with the Azure Firewall, even if the intent was to use it only for DNAT, will be used for outbound SNAT. 

If you'd like to use a separate set of Public IPs for outbound traffic and to alleviate SNAT exhaustion, you can configure a NAT Gateway on the AzureFirewallSubnet so that the Public IPs associated with the Azure Firewall will be used for inbound only. To find more information about this, you can read more here: Tutorial: Integrate NAT gateway with Azure Firewall in a hub and spoke network - Azure NAT Gateway | Microsoft Learn

Thanks