> But it simply doesn't work. My work involves writing software for big routers and switches used by ISPs, data centers, campuses, etc. and I can guarantee you

> But it simply doesn't work. My work involves writing software for big routers and switches used by ISPs, data centers, campuses, etc. and I can guarantee you that a router will 100% switch/route your exotic packets with an unknown L4 protocol number. It literally does not care about anything past the IP header. There are a few things I can think of that may have led to your experience, one of them is NAT. Well, NAT just sucks. It is the reason why I want IPv4 to die. Just getting rid of NAT will be worth the pain of switching to IPv6. PS - IPv6 NAT is just downright stupid.