RPL was developed as a routing protocol in low-power and lossy network contexts to connect many applications using IP-based communication. However, RPL has been subjected to several attacks, including replay attacks. Replay attacks pose significant challenges as any node can initiate the attack by replaying control messages. These messages play a vital role in establishing and sustaining network topology. However, studies that discourse replay attacks are severely limited. To address this issue, we conducted a comprehensive study on replay attack forms and their impact on RPL networks. Our study includes the latest security countermeasures. According to the literature, most RPL replay attacks rely on replaying DIO messages leading to neighbor, DIO suppression, or copycat attacks. DAO messages are also utilized to launch a replay attack. Nevertheless, the literature lacks any study that analyzes DAO replay attacks. To the best of our knowledge, this is the first study that evaluates DAO replay attacks and includes the route table falsification attack.We conduct a comparative study of these attacks and empirically investigate their impact on networks through extensive evaluation experiments. Our findings verify the harm of replay attacks in terms of packet delivery and latency. The average local delivery ratio dropped to less than 60% under DIO suppression and copycat attacks, and the communication latency increased by 50% under neighbor attacks. These results confirm the threat of replay attacks on RPL networks and the need to design countermeasures to mitigate them.