10.2.1 Minimum Router Configuration

There exists a minimum set of conditions that must be satisfied before a router may forward packets. A router MUST NOT enable forwarding on any physical interface unless either:

1. The router knows the IP address and associated subnet mask or network prefix length of at least one logical interface associated with that physical interface, or

2. The router knows that the interface is an unnumbered interface and knows its router-id.

These parameters MUST be explicitly configured:

• A router MUST NOT use factory-configured default values for its IP addresses, prefix lengths, or router-id, and

• A router MUST NOT assume that an unconfigured interface is an unnumbered interface.

DISCUSSION

There have been instances in which routers have been shipped with vendor-installed default addresses for interfaces. In a few cases, this has resulted in routers advertising these default addresses into active networks.