diff --git a/main.py b/main.py
index 18585cb..a0b97c4 100755
--- a/main.py
+++ b/main.py
@@ -475,44 +475,46 @@ class iptables:
         self.init_nat(subtable, decision="-")
         self.jump_all_trafic("nat", "POSTROUTING", subtable, mode='4')
 
-        nat_prive_ip_plage = nat_type['ip_sources']
-        for nat_ip_range in range(1, 11):
-            range_name = 'nat' + nat_prive_ip_plage.split('.')[1] + '_' + str("%02d" % nat_ip_range )
-            self.init_nat(range_name, decision="-")
-            self.add_in_subtable("nat4", subtable, '-s ' + '.'.join(nat_prive_ip_plage.split('.')[:2]) + '.' + str(nat_ip_range) + '.0/24 -j ' + range_name)
-        for nat_ip_range in range(1, 11):
-            range_name = 'nat' + nat_prive_ip_plage.split('.')[1] + '_' + str("%02d" % nat_ip_range)
-            nat_rule_tcp = ""
-            nat_rule_udp = ""
-            for nat_ip_subrange in range(16):
-                subrange_name = range_name + '_' + str(hex(nat_ip_subrange)[2:])
-                self.init_nat(subrange_name, decision="-")
-                self.add_in_subtable("nat4", range_name, '-s ' + '.'.join(nat_prive_ip_plage.split('.')[:2]) + '.' + str(nat_ip_range) + '.' + str(nat_ip_subrange*16) + '/28 -j ' + subrange_name)
-            for nat_private_ip in range(256):
-                ip_src = '.'.join(nat_prive_ip_plage.split('.')[:2]) + '.' + str(nat_ip_range) + '.' + str(nat_private_ip) + '/32'
+        if 'interfaces_ip_to_nat' in nat_type and 'ip_sources' in nat_type:
+            nat_prive_ip_plage = nat_type['ip_sources']
+            for nat_ip_range in range(1, 11):
+                range_name = 'nat' + nat_prive_ip_plage.split('.')[1] + '_' + str("%02d" % nat_ip_range )
+                self.init_nat(range_name, decision="-")
+                self.add_in_subtable("nat4", subtable, '-s ' + '.'.join(nat_prive_ip_plage.split('.')[:2]) + '.' + str(nat_ip_range) + '.0/24 -j ' + range_name)
+            for nat_ip_range in range(1, 11):
+                range_name = 'nat' + nat_prive_ip_plage.split('.')[1] + '_' + str("%02d" % nat_ip_range)
+                nat_rule_tcp = ""
+                nat_rule_udp = ""
+                for nat_ip_subrange in range(16):
+                    subrange_name = range_name + '_' + str(hex(nat_ip_subrange)[2:])
+                    self.init_nat(subrange_name, decision="-")
+                    self.add_in_subtable("nat4", range_name, '-s ' + '.'.join(nat_prive_ip_plage.split('.')[:2]) + '.' + str(nat_ip_range) + '.' + str(nat_ip_subrange*16) + '/28 -j ' + subrange_name)
+                for nat_private_ip in range(256):
+                    ip_src = '.'.join(nat_prive_ip_plage.split('.')[:2]) + '.' + str(nat_ip_range) + '.' + str(nat_private_ip) + '/32'
 
-                port_low = 1000 + 1000*(nat_private_ip%64)
-                port_high = port_low + 999
+                    port_low = 1000 + 1000*(nat_private_ip%64)
+                    port_high = port_low + 999
 
-                subrange_name = range_name + '_' + str(hex(nat_private_ip//16)[2:])
+                    subrange_name = range_name + '_' + str(hex(nat_private_ip//16)[2:])
 
-                # On nat
+                    # On nat
 
-                for interface, pub_ip_range in nat_type['interfaces_ip_to_nat'].items():
-                    ip_nat = '.'.join(pub_ip_range.split('.')[:3]) + '.' + str((int(nat_prive_ip_plage.split('.')[1][0]) - 1)*40 + 4*(nat_ip_range - 1) + nat_private_ip//64)
-                    nat_rule_tcp += '\n-A %s -s %s -o %s -p tcp -j SNAT --to-source %s' % (subrange_name, ip_src, interface, ip_nat + ':' + str(port_low) + '-' + str(port_high))
-                    nat_rule_udp += '\n-A %s -s %s -o %s -p udp -j SNAT --to-source %s' % (subrange_name, ip_src, interface, ip_nat + ':' + str(port_low) + '-' + str(port_high))
-            self.add("nat4", nat_rule_tcp)
-            self.add("nat4", nat_rule_udp)
+                    for interface, pub_ip_range in nat_type['interfaces_ip_to_nat'].items():
+                        ip_nat = '.'.join(pub_ip_range.split('.')[:3]) + '.' + str((int(nat_prive_ip_plage.split('.')[1][0]) - 1)*40 + 4*(nat_ip_range - 1) + nat_private_ip//64)
+                        nat_rule_tcp += '\n-A %s -s %s -o %s -p tcp -j SNAT --to-source %s' % (subrange_name, ip_src, interface, ip_nat + ':' + str(port_low) + '-' + str(port_high))
+                        nat_rule_udp += '\n-A %s -s %s -o %s -p udp -j SNAT --to-source %s' % (subrange_name, ip_src, interface, ip_nat + ':' + str(port_low) + '-' + str(port_high))
+                self.add("nat4", nat_rule_tcp)
+                self.add("nat4", nat_rule_udp)
 
-        # On nat tout ce qui match dans les règles et qui n'est pas du tcp/udp derrière la première ip publique unused (25*10) + 1
-        # Ne pas oublier de loguer ce qui sort de cette ip
-        for interface, pub_ip_range in nat_type['interfaces_ip_to_nat'].items():
-            self.add_in_subtable("nat4", subtable, '-s ' + nat_prive_ip_plage + ' -o %s -j SNAT --to-source ' % (interface,)  + '.'.join(pub_ip_range.split('.')[:3]) + '.' + str(250 + int(nat_prive_ip_plage.split('.')[1][0])))
+            # On nat tout ce qui match dans les règles et qui n'est pas du tcp/udp derrière la première ip publique unused (25*10) + 1
+            # Ne pas oublier de loguer ce qui sort de cette ip
+            for interface, pub_ip_range in nat_type['interfaces_ip_to_nat'].items():
+                self.add_in_subtable("nat4", subtable, '-s ' + nat_prive_ip_plage + ' -o %s -j SNAT --to-source ' % (interface,)  + '.'.join(pub_ip_range.split('.')[:3]) + '.' + str(250 + int(nat_prive_ip_plage.split('.')[1][0])))
 
-        ### Extra-nat (ex : Pour que le routeur ait accès à internet)
-        for ip_source, ip_to_nat in nat_type['extra_nat'].items():
-            self.add_in_subtable("nat4", subtable, '-s ' + ip_source + ' -j SNAT --to-source ' + ip_to_nat)
+        if 'extra_nat' in nat_type:
+            ### Extra-nat (ex : Pour que le routeur ait accès à internet)
+            for ip_source, ip_to_nat in nat_type['extra_nat'].items():
+                self.add_in_subtable("nat4", subtable, '-s ' + ip_source + ' -j SNAT --to-source ' + ip_to_nat)
 
     def gen_mangle(self, empty=False):
         """Génération de la chaine mangle"""