The problem is that you're pinging from the WAN side, but your tunnel
exists from your LAN IP's.  You need to change the source address from
which you are pinging from to the LAN side.  Go to exec.php, and paste
the following command in m0n0wall-1:

/sbin/ping -c 10 -S 192.168.90.4 192.168.100.250

This should work as expected.  If not, your tunnels aren't configured
quite properly.


-- 
Justin Ellison <justin at techadvise dot com>