A default route Azure creates automatically for each subnet, such as traffic within the VNet or 0.0.0.0/0 to the Internet. UDRs override them.
Read more: Microsoft Learn
In the Ultra Transcenders books
Each book explains System route in context, with comparison tables and the common traps.
Terms in this definition
- Default route
The 0.0.0.0/0 route matching any destination. Advertised by on-premises routers through BGP on ExpressRoute private peering (Microsoft peering won't do), it sends internet traffic from connected VNets back on-premises.
- Subnet
A segment of a VNet's address space from which resources receive private IPs. Azure holds back five addresses per subnet (the first four and the last), leaving 251 usable in a /24 and three in a /29, the smallest IPv4 subnet.
- VNet
A private network belonging to a single subscription and region and covering all of that region's availability zones. A VM can only use a VNet located in the same region.
Related terms
- Network Watcher next hop
Use it to troubleshoot routing for a destination: it returns the route table in effect (System Route or a UDR's table) with the next hop's type and IP. NSG filtering is not examined.