Did you patch the kernel using NAT-T patch ? And
did you turn on the nat_traversal ?
It happens to my system too where I have
nat-t patch, but nat_traversal is disabled (default) in
freeswan configuration, then I put in a rule like this :-
iptables -t nat -I PREROUTING -p esp
When I list the rule, I can't see any packet going thru' it.
Regards.
