nathelper module has this variable:
4.3. ping_nated_only (integer)
If this variable is set then only contacts that have "behind_NAT" flag
in user location database set will get ping.
i.e. nat pinging is bound to contact being behind nat.
in case of outbound, even if contact is behind nat, it should be
excluding from nat pinging. this seems to be currently impossible.
looks like there should be two separate usrloc flags: the current
"behind_NAT" flag and a new "NAT_ping_this_contact" flag.
comments?
-- juha