A story about bypassing air Canada's in-flight network restrictions

If a ping to a specific IP times out, I wouldn't say the IP is blocked. It could be that ICMP specifically is blocked, following some network rules on the firewall. This is pretty common in entreprise networks to not allow endpoint discovery. I could be missing something and happy to be corrected here, but I was surprised to read that.

I’ve had to explain this over and over throughout my career. The only way to know if something is accessible is to try the exact endpoint and protocol. Even application-aware firewalls will mess with things at times.