route_metric

The default metric for routes that don't explicitly specify a metric.

The default value -1 means that the metric is chosen automatically based on the device type. The metric applies to dynamic routes, manual (static) routes that don't have an explicit metric setting, address prefix routes, and the default route. As the linux kernel replaces zero (0) by 1024 (user-default), setting this property to 0 means effectively setting it to 1024.