There are a few different setting for source traffic. The source traffic needs to be categorized first. An important setting is the Tag categorization. This makes it possible to choose from the Source from Internet, AzureLoadBalancer, and VirtualNetwork. Where Internet means the public IP address space, VirtualNetwork the private and virtual address space, and AzureLoadBalancer the traffic that originates from deployed load balancers to determine the service health.

The last setting is the Protocol. There are many service templates for common services such as RDP, SMTP, or FTP. This makes it easy to quickly create some rules in the portal.