The topic was specifically ICMP, so I addressed that. I didn't want to stray too far off topic, so I left it at that. I had / have a little project running tha

The topic was specifically ICMP, so I addressed that. I didn't want to stray too far off topic, so I left it at that. I had / have a little project running that detects "uninvited activity" on my systems, and blocks traffic (including ICMP) to and from those sources based on a few rules. https://github.com/UninvitedActivity/UninvitedActivity https://github.com/UninvitedActivity/UninvitedActivity It needs some maintenance, so I sometimes avoid mentioning it. ICMP can be a special case because of the reasons mentioned in the article and other replies, such is why I addressed it separately from other types of blocking (eg. ports). The main point I wanted to make in my original comment was that my blocking of ICMP from 'trash' sources causes my internet experience no problems; that whilst blanket blocking ICMP may not be a good idea, selective blocking doesn't seem to be a problem.