[Warhammer]

ICMP (Internet Control Message Protocol) packets by themselves are harmless and are not going to be investigated by any ISP or security organization. ICMP, like TCP and UDP, is one of the primary protocols that ensures the Internet functions the way it is supposed to.

ICMP is used to send state information about the network between hosts. The two most popular ICMP uses are "ping" and "traceroute". However there are actually about three dozen other uses for ICMP, including detecting when Internet links go down and bypassing them, adjusting the data packet size, and notifying when packets are being sent to a system that doesn't exist on the network.

My advice (and I am a security person) is to ignore it, unless there is an indication that your system is vulnerable to some kind of ICMP attack (like Smurf, which is unlikely). If it was a simple "ping" packet, billions of these fly around the Internet every day and are so much noise in the song of the ether.