IPENCAP getting dropped

Hi all,

I'm having a problem with IPENCAP in that MW keeps dropping/blocking the 
incoming packets.

Mine is an amateur radio application where we use the 44.0.0.0/8 subnet. 
As we are not allowed to interface with the "normal" Internet we use 
IPENCAP to tunnel our data from one place to another.

The problem is that when incoming data gets to my monowall (running 
V1.3) the packets get dropped.

Interestingly, if the remote station sends me an IPENCAP packet (for 
example a ping) his packets are dropped. If I then send him data 
immediately we can both swap data for quite a while until (I'm guessing) 
some TTL has expired. I can produce this in both directions; the second 
person to send data is able to conduct a data swapping session.

Any ideas?

Thanks

Mark