Azure User-Defined Routes (UDRs) allow you to define custom routing rules for network traffic in your Azure virtual network (VNet). UDRs can be used to control the flow of traffic between subnets or between the VNet and other networks.
Here are a few examples of how UDRs can be used:
- Control traffic flow between subnets: You can use UDRs to control traffic flow between subnets within the same VNet. For example, you might want to route traffic between two subnets through a network virtual appliance (NVA) for security or traffic optimization reasons.
- Control traffic flow between VNets: If you have multiple VNets connected through a VNet peering or VPN gateway connection, you can use UDRs to control traffic flow between the VNets. For example, you might want to route traffic between two VNets through an NVA or a VPN gateway.
- Route traffic to the internet: By default, all traffic from an Azure VNet is routed directly to the internet. You can use UDRs to route traffic through an NVA or other gateway device to provide additional security or traffic optimization.
- Route traffic to on-premises networks: If you have a VPN gateway or ExpressRoute connection to an on-premises network, you can use UDRs to control the flow of traffic between the VNet and the on-premises network.
Overall, UDRs provide a flexible way to define custom routing rules in your Azure virtual network to meet your specific network requirements.
