What's peculiar about a lot of these non-44 is that they have
the encapsulated (inner) source and destination apparently interchanged:
Apr 19 21:28:27 <local0.debug> amprgw ipipd[66472]: NON44: len 40,
os 91.121.90.186, od 169.228.66.251, is 91.223.133.13, id 44.134.209.15,
ttl 237, proto 6
Either that or they're encapping in the wrong direction.
I can't offhand think of what would cause THAT.
- Brian