diff --git a/gestion/gen_confs/firewall4.py b/gestion/gen_confs/firewall4.py
index baa5cd33..e88945ba 100755
--- a/gestion/gen_confs/firewall4.py
+++ b/gestion/gen_confs/firewall4.py
@@ -406,8 +406,9 @@ class firewall_base(object) :
         for ip in ip_list:
             machine = conn.search("ipHostNumber=%s" % ip)
             if machine:
-                try: self.test_mac_ip_dispatch(lambda set, data: self.ipset['mac_ip'][set].add(data), machine[0])
+                try: self.test_mac_ip_dispatch(lambda set, data: self.ipset['mac_ip'][set].delete(data.split(',',1)[0]), {'ipHostNumber' : [ip], 'macAddress':[''] })
                 except IpsetError: pass
+                self.test_mac_ip_dispatch(lambda set, data: self.ipset['mac_ip'][set].add(data), machine[0])
             else:
                 try: self.test_mac_ip_dispatch(lambda set, data: self.ipset['mac_ip'][set].delete(data.split(',',1)[0]), {'ipHostNumber' : [ip], 'macAddress':[''] })
                 except IpsetError: pass