This doesn't appear to cause any unwanted effects so it's more of a
curiosity at the moment. I've found that if, while pinging an
external host, I send a ping from that host to my m0n0wall, the ping
fails and I don't get a reply until I stop for some time. When I
check the logs, I see that my m0n0 has been blocking all the dropped
pings. Why is this? Is it a consequence of NAT?