CREST Practitioner Security Analyst (CPSA) Practice

What protocol uses port 520 for routing updates?

1. RIP

2. OSPF

3. BGP

4. EIGRP

The correct answer is: RIP

The protocol that utilizes port 520 for routing updates is Routing Information Protocol (RIP). RIP is a distance-vector routing protocol that is designed to facilitate the exchange of routing information within an autonomous system. It employs a simple algorithm, counting hops as the metric for routes, with a maximum limit of 15 hops, which makes it suitable for smaller networks. RIP broadcasts its routing updates every 30 seconds, and it listens for updates on port 520. This well-known port number ensures that RIP messages are received appropriately by the routers that implement the protocol. Understanding port assignments is crucial in network protocols, as it determines how routers communicate with one another in a given configuration. This is particularly important in scenarios that involve troubleshooting or setting up network equipment, where knowing which protocols operate over which ports can aid in diagnosing issues or configuring firewalls effectively. In contrast, other protocols like OSPF (Open Shortest Path First), BGP (Border Gateway Protocol), and EIGRP (Enhanced Interior Gateway Routing Protocol) use different mechanisms and do not utilize port 520 for their routing updates. OSPF primarily uses multicast addresses, BGP employs port 179, and EIGRP relies on its own encapsulation rather than a designated port