IGMP (Internet Group Management Protocol) is used by IPv4 systems to transmit multicast group membership information to routers. It may also be used for other IP multicast management functions.IGMP is an integral part of IPv4. It is present at least to some extent in almost all modern IP networking equipment. Since a well-functioning IP stack implementation is the cornerstone of any IP switch, router or host system, the robustness of the IP implementation is an all-important factor in the overall robustness of the device in question. As IGMP forms an integral part of the IP implementation, the IGMP message handling routines inside the IP stack should be verified and proven against protocol attacks. Robustness shortcomings in core IP services result in undesirable network downtime and denial-of-service conditions. Entire networks may be rendered inaccessible to their customers. Therefore knowledge about the level of security in components that may be exposed to external intrusion attempts is absolutely crucial. This information is invaluable in mitigating threats and performing informed risk analysis. To guarantee the continuous and error-free operation of the current and future Internet, the dependability of IP protocol implementations must be verified.