diff --git a/gestion/config/trigger.py b/gestion/config/trigger.py
index 564ebe30..1763135a 100644
--- a/gestion/config/trigger.py
+++ b/gestion/config/trigger.py
@@ -15,7 +15,7 @@ services = {
             'dhcp'      : ["dhcp"],
             'dyson'     : ["autostatus"],
             'isc'       : ["dhcp"],
-            'komaz'     : ["mac_ip", "secours"],
+            'komaz'     : ["firewall", "secours"],
             'owl'       : ["userdel"],
             'redisdead' : ["mailman", "modif_ldap", "solde", "userdel", "secours"],
             'sable'     : ["dns"],
diff --git a/gestion/trigger/firewall4 b/gestion/trigger/firewall4
new file mode 120000
index 00000000..7aeba490
--- /dev/null
+++ b/gestion/trigger/firewall4
@@ -0,0 +1 @@
+../gen_confs/firewall4
\ No newline at end of file
diff --git a/gestion/trigger/services/event.py b/gestion/trigger/services/event.py
index 7e8fd5a0..e4fa935b 100644
--- a/gestion/trigger/services/event.py
+++ b/gestion/trigger/services/event.py
@@ -15,7 +15,7 @@ import cranslib.clogger as clogger
 import pika
 import lc_ldap.attributs
 
-logger = clogger.CLogger("trigger", "info")
+logger = clogger.CLogger("trigger.event", "info")
 
 class Event(cmb.BasicProducer):
     """
@@ -128,6 +128,8 @@ def event(body=()):
 
     """
 
+    logger.info("Received message %s…", body)
+
     diff = diff_o_matic(body)
 
     # À cette étape, on a un dico des attrs ayant subi une modif
@@ -140,6 +142,7 @@ def event(body=()):
 
     # Si la mac ou l'IP a changé…
     if diff.has_key(lc_ldap.attributs.ipHostNumber.ldap_name) or diff.has_key(lc_ldap.attributs.macAddress.ldap_name):
+        logger.info("Detected MAC or IP update, calling trigger_mac_ip…", body)
         trigger_mac_ip(body, diff)
 
 def trigger_mac_ip(body, diff):
@@ -150,17 +153,18 @@ def trigger_mac_ip(body, diff):
     # Régénération du DHCP :
     if not macs[0]:
         # Création d'une nouvelle machine.
-        to_send = {'add': (macs[1], ips[1], hostnames[1])}
+        dhcp = {'add': (macs[1], ips[1], hostnames[1])}
+        fw = {'add': (macs[1], ips[1])}
     elif not macs[1]:
         # Destruction d'une machine.
         to_send = {'delete': (macs[0], ips[0])}
+        fw = {'delete': (macs[0], ips[0])}
     else:
         # Mise à jour.
         to_send = {'update': (macs[0], ips[0], macs[1], ips[1], hostnames[1])}
+        fw = {'update': (macs[0], ips[0], macs[1], ips[1])}
     trigger_send('dhcp', to_send)
-
-    # Régénération du parefeu.
-    trigger_send('mac_ip', to_send)
+    trigger_send('firewall_mac_ip', fw)
 
 def trigger_send(ttype, to_send):
     print "Sending trigger %s with %s…" % (ttype, to_send)
diff --git a/gestion/trigger/services/firewall.py b/gestion/trigger/services/firewall.py
new file mode 100644
index 00000000..983f0f26
--- /dev/null
+++ b/gestion/trigger/services/firewall.py
@@ -0,0 +1,150 @@
+#!/bin/bash /usr/scripts/python.sh
+# -*- coding: utf-8 -*-
+#
+# Service in charge of firewall for trigger.
+#
+# Author : Pierre-Elliott Bécue <becue@crans.org>
+# Licence : GPLv3
+
+import lc_ldap.shortcuts
+from gestion.trigger.host import record
+import cranslib.clogger as clogger
+import gestion.config.dhcp as dhcp_config
+import gestion.secrets_new as secrets_new
+import socket
+import gestion.affichage as affichage
+import os
+import sys
+import gestion.iptools as iptools
+
+logger = clogger.CLogger("trigger.firewall", "debug")
+hostname = socket.gethostname().split(".")[0] + ".adm.crans.org"
+dhcp_omapi_keyname = secrets_new.get("dhcp_omapi_keyname")
+dhcp_omapi_key = secrets_new.get("dhcp_omapi_keys")[hostname]
+ldap_conn = lc_ldap.shortcuts.lc_ldap_readonly()
+
+def add_dhcp_host(mac, ip, name=None):
+    """Adds a dhcp host using omapi
+
+    """
+
+    if '<automatique>' in [ip, mac]:
+        return
+    msg = OmapiMessage.open(b"host")
+    msg.message.append((b"create", struct.pack("!I", 1)))
+    msg.message.append((b"exclusive", struct.pack("!I", 1)))
+    msg.obj.append((b"hardware-address", pack_mac(mac)))
+    msg.obj.append((b"hardware-type", struct.pack("!I", 1)))
+    msg.obj.append((b"ip-address", pack_ip(ip)))
+    if name:
+        msg.obj.append((b"name", bytes(name)))
+    conn = Omapi(hostname, 9991, dhcp_omapi_keyname, dhcp_omapi_key)
+    response = conn.query_server(msg)
+    conn.close()
+
+def delete_dhcp_host(self, mac, ip):
+    """Deletes dhcp host using omapi
+
+    """
+
+    if '<automatique>' in [ip, mac]:
+        return
+    msg = OmapiMessage.open(b"host")
+    msg.obj.append((b"hardware-address", pack_mac(mac)))
+    msg.obj.append((b"hardware-type", struct.pack("!I", 1)))
+    msg.obj.append((b"ip-address", pack_ip(ip)))
+    conn = Omapi(hostname, 9991, dhcp_omapi_keyname, dhcp_omapi_key)
+    response = conn.query_server(msg)
+    if response.opcode == OMAPI_OP_UPDATE:
+        response = conn.query_server(OmapiMessage.delete(response.handle))
+    conn.close()
+
+def lease_clean():
+    """Clean the lease file
+
+    """
+    # TODO : use ConfigFile structure
+    leasefile = open(dhcp_config.dhcplease)
+    newleasefile = open(dhcp_config.dhcplease + '.new', 'w')
+    config = ""
+    line = leasefile.readline()
+    write = True
+    while line:
+        if line.strip().startswith('host'):
+            write = False
+        if write:
+            newleasefile.write(line)
+        if not write and line.strip().endswith('}'):
+            write = True
+        line = leasefile.readline()
+    leasefile.close()
+    newleasefile.close()
+    os.rename(dhcp_config.dhcplease+'.new', dhcp_config.dhcplease)
+
+@record
+def dhcp(body={}):
+    """Regenerates dhcp service taking body into account.
+
+    """
+    if body and isinstance(body, dict):
+        for (mac, ip, name) in body.get("add", ()):
+            add_dhcp_host(mac, ip, name)
+        for (mac, ip) in body.get("delete", ()):
+            delete_dhcp_host(mac, ip)
+        for (rmac, rip, mac, ip, name) in body.get("update", ()):
+            delete_dhcp_host(rmac, rip)
+            add_dhcp_host(mac, ip, name)
+    elif body == True:
+        hosts = {}
+        host_template = """
+    host %(nom)s {
+        hardware ethernet %(mac)s;
+        fixed-address %(ip)s;
+        option host-name "%(host)s";
+    }
+"""
+        affichage.prettyDoin("Chargement des machines", "...")
+        machines = ldap_conn.allMachines()
+        affichage.prettyDoin("Chargement des machines", "Ok")
+        animation = affichage.Animation(texte="Génération de la configuration",
+                                        nb_cycles=len(machines),
+                                        couleur=True,
+                                        kikoo=True)
+
+        for machine in machines:
+            for net in dhcp_config.reseaux.keys():
+                ip = str(machine['ipHostNumber'][0])
+                mac = str(machine['macAddress'][0])
+                nom = str(machine['host'][0])
+                if '<automatique>' not in [ip, mac] and iptools.AddrInNet(ip, net):
+                    d = {'nom' : nom,
+                         'host' : nom.split(".", 1)[0],
+                         'mac' : mac,
+                         'ip' : ip,
+                        }
+                    try:
+                        hosts[net] += host_template % d
+                    except:
+                        hosts[net] = host_template % d
+            animation.new_step()
+        # Put a \n after the last iteration.
+        animation.end()
+
+        step = "Enregistrement de la configuration dans les fichiers"
+        affichage.prettyDoin(step, "...")
+        for (net, fichier) in dhcp_config.reseaux.items():
+            with ConfFile(fichier) as configFile:
+                configFile.header("#")
+                if hosts.has_key(net):
+                    configFile.write(hosts[net])
+        affichage.prettyDoin(step, "Ok")
+
+        step = "Nettoyage des fichiers de leases"
+        affichage.prettyDoin(step, "...")
+        try:
+            lease_clean()
+            affichage.prettyDoin(step, "Ok")
+        except:
+            affichage.prettyDoin(step, "Erreur")
+            print "During lease clean, an error occured."
+            raise