Are there any other implications to turning off ICMP packets at the router? Where my wife works, someone complained that they could not access my wife's employer's site because ICMP packets were turned off. Was that a valid issue or were they using that as an excuse for another problem?
Blocking ALL ICMP packets can cause a variety of problems. I'm no expert on this, but it's my understanding that there are many ICMP packets, besides PINGs (type 8) and PING response (type 0). According to the sources I have, you generally need to allow Source Quench (type 4), Parameter Problem (type 12), incoming Destination Unreachable (type 3) and outgoing Fragmentation Needed (type 3, subtype frag. needed).
Blocking PINGs won't make a site inaccessible, but blocking all ICMP traffic might.