Also ptunnel comes standard with some linux distro's these days Ubuntu and so do probably most of it's derivatives, and as far as raw performance goes ptunnel is also the highest performing one capable of achieving about 150kbps which isn't that bad considering the sheer amount of packets and overhead you get.
http://manpages.ubuntu.com/manpages/gutsy/man8/ptunnel.8.htm...
What's your question? Is it "What's the point of blocking ICMP?"? Or is it the opposite question?
If it's the former, then there are sysadmins out there who cargo-cult their network configuration and listen to folks like Gibson Research Corporation who've been giving really bad advice [0] for the past decade+.
[0] Specifically, they strongly recommend dropping all traffic to ports that don't have listening services, along with all ICMP, rather than rejecting said traffic and allowing all non-problematic ICMP. They also have a "handy" tool [1] to make it look like doing anything else is "DANGEROUS": (The tool reports [2] if your site responds to ICMP echo requests.)
[1] https://www.grc.com/shieldsup
[2] Ping Reply: RECEIVED (FAILED) — Your system REPLIED to our Ping (ICMP Echo) requests, making it visible on the Internet. Most personal firewalls can be configured to block, drop, and ignore such ping requests in order to better hide systems from hackers. This is highly recommended since "Ping" is among the oldest and most common methods used to locate systems prior to further exploitation.
Any captive portal these days block also ICMP.
Most firewalls block ICMP these days, because the days of blacklisting are over and ICMP is not the one who is getting white listed. Why?
The only way these days is to misuse DNS. But even that works less and less reliable.