Which port is used by followers to connect to the active leader?

• A. Client port
• B. Election port
• C. Data port
• D. Leader port

Answer: (D)

In a system that uses a leader-follower replication model, the followers stay in sync by connecting to the current active leader to fetch and apply updates. This replication traffic happens over a dedicated port on the leader that is intended for inter-broker communication. That port is what followers use to establish the replication session and receive new log entries from the leader, keeping the follower replicas up to date.

The client port is reserved for end-user clients (producers and consumers) to connect to brokers, not for replication between brokers. The election port is only involved during the process of electing a new leader and isn’t used for ongoing replication once leadership is established. The data port isn’t a standard term used for this purpose in the typical replication setup. Therefore, the port used by followers to connect to the active leader is the Leader port.