actually, why do people block ICMP? I remember in 1997-1998 there were some Cisco ICMP vulnerabilities and people started blocking ICMP then and mostly never stopped, and I never understood why. ICMP is so valuable for troubleshooting in certain situations.
Security through obscurity mostly, I don't know who continues to push the advice to block ICMP without a valid technical reason since at best if you tilt your head and squint your eyes you could almost maybe see a (very new) script kiddie being defeated by it.
I've rarely actually seen that advice anywhere, more so 20 years ago than now but people are still clearly getting it from circles I don't run in.
actually, why do people block ICMP? I remember in 1997-1998 there were some Cisco ICMP vulnerabilities and people started blocking ICMP then and mostly never stopped, and I never understood why. ICMP is so valuable for troubleshooting in certain situations.