update freedns usage

UsefullfreeDNS.md

@@ -22,4 +22,24 @@ PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin
 
 4,9,14,19,24,29,34,39,44,49,54,59 * * * * sleep 48 ; wget --no-check-certificate -O - https://freedns.afraid.org/dynamic/update.php?YWVjZFVoFDersdeghgd12SlFIeFBIOjIxMGfdt56E5 >> /tmp/freedns_townname_nationname_mooo_com.log 2>&1 &
 
-```
+```
+
+Then you need to set your box to route request from port 80 or 443 to your server. We mainly have 2 options for this:
+
+* DMZ (Demilitarized zone): any external trafic is route to one machine 
+
+* NAT (Network Address Translation) let you change external IP address and port to other IP and port into your LAN (local network). 
+
+Usualy acces to your local router in your browser with 192.168.1.1
+
+Example with orange.fr operator in france: 
+All external trafic is send to a dmsz 192.168.1.17
+!(dmz orange)[img/orangeDMZ.png] 
+
+External IP (let tous) request on port X can be redirect to 192.168.1.17 to a new port 
+!(nat orange)[img/orangeNAT.png]
+
+
+
+
+