Final answer:
The passive-interface command in RIP stops the interface from sending updates but it does not block receiving updates. It's used to control outbound routing advertisements while still allowing the router to listen for incoming routing information.
Step-by-step explanation:
In the context of Routing Information Protocol (RIP), the passive-interface command is used to control the advertisement of routing information. Using passive-interface in RIP configuration mode on a router interface will prevent that interface from sending RIP updates. However, it is important to note that even if an interface is passive, the router will still listen for RIP updates on that interface unless there is an explicit configuration in place to block incoming updates.
The primary function of the passive-interface command is to stop the router from potentially advertising routes on networks where routing updates are not desired, such as in the direction of an end-user segment. This reduces unnecessary network traffic and enhances security by not disclosing routing information to unwanted locations.