Internet-of-Things (IoT) networks are characterized by low-powered nodes with limited computational power and storage capacity. Consequently, protocols dedicated to Low Power and Lossy networks (LLNs) are designed to support communication in such resource-constrained nodes. One such protocol is Routing Protocol for Low-Power and lossy networks (RPL) which builds and maintains routes in RPL-based networks, leading to optimized routing and lower network overhead. However, the RPL-based protocol has several internal and external vulnerabilities that must be explored and addressed. Therefore, the present study illustrates the impact of several RPL-based attacks, including DIS attack, version number attack, decreased rank attack, and WPS attack, by employing the Contiki Cooja network simulator with specific simulation scenarios. In addition, we conduct a comparative analysis of the RPL-based attacks and find that the WPS attack results in the highest packet loss rate of 26%, whereas the DIS attack, version number attack, and rank attack result in packet loss rates of 17%, 15%, and 13%, respectively.