diff --git a/cotisations/migrations/0024_auto_20171015_2033.py b/cotisations/migrations/0024_auto_20171015_2033.py
new file mode 100644
index 00000000..b52dad62
--- /dev/null
+++ b/cotisations/migrations/0024_auto_20171015_2033.py
@@ -0,0 +1,26 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.7 on 2017-10-15 18:33
+from __future__ import unicode_literals
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('cotisations', '0023_auto_20170902_1303'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='article',
+            name='duration',
+            field=models.PositiveIntegerField(blank=True, help_text='Durée exprimée en mois entiers', null=True, validators=[django.core.validators.MinValueValidator(0)]),
+        ),
+        migrations.AlterField(
+            model_name='vente',
+            name='duration',
+            field=models.PositiveIntegerField(blank=True, help_text='Durée exprimée en mois entiers', null=True),
+        ),
+    ]
diff --git a/cotisations/models.py b/cotisations/models.py
index 54843076..0b3aef35 100644
--- a/cotisations/models.py
+++ b/cotisations/models.py
@@ -132,7 +132,7 @@ class Vente(models.Model):
     name = models.CharField(max_length=255)
     prix = models.DecimalField(max_digits=5, decimal_places=2)
     iscotisation = models.BooleanField()
-    duration = models.IntegerField(
+    duration = models.PositiveIntegerField(
         help_text="Durée exprimée en mois entiers",
         blank=True,
         null=True)
@@ -222,7 +222,7 @@ class Article(models.Model):
     name = models.CharField(max_length=255, unique=True)
     prix = models.DecimalField(max_digits=5, decimal_places=2)
     iscotisation = models.BooleanField()
-    duration = models.IntegerField(
+    duration = models.PositiveIntegerField(
         help_text="Durée exprimée en mois entiers",
         blank=True,
         null=True,
diff --git a/machines/migrations/0061_auto_20171015_2033.py b/machines/migrations/0061_auto_20171015_2033.py
new file mode 100644
index 00000000..6153bbd0
--- /dev/null
+++ b/machines/migrations/0061_auto_20171015_2033.py
@@ -0,0 +1,36 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.7 on 2017-10-15 18:33
+from __future__ import unicode_literals
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('machines', '0060_iptype_ouverture_ports'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='mx',
+            name='priority',
+            field=models.PositiveIntegerField(unique=True),
+        ),
+        migrations.AlterField(
+            model_name='ouvertureport',
+            name='begin',
+            field=models.PositiveIntegerField(validators=[django.core.validators.MaxValueValidator(65535)]),
+        ),
+        migrations.AlterField(
+            model_name='ouvertureport',
+            name='end',
+            field=models.PositiveIntegerField(validators=[django.core.validators.MaxValueValidator(65535)]),
+        ),
+        migrations.AlterField(
+            model_name='vlan',
+            name='vlan_id',
+            field=models.PositiveIntegerField(validators=[django.core.validators.MaxValueValidator(4095)]),
+        ),
+    ]
diff --git a/machines/models.py b/machines/models.py
index 7444996c..0c1686ba 100644
--- a/machines/models.py
+++ b/machines/models.py
@@ -151,10 +151,11 @@ class IpType(models.Model):
         return self.type
 
 class Vlan(models.Model):
-    """ Un vlan : vlan_id et nom"""
+    """ Un vlan : vlan_id et nom
+    On limite le vlan id entre 0 et 4096, comme défini par la norme"""
     PRETTY_NAME = "Vlans"
 
-    vlan_id = models.IntegerField()
+    vlan_id = models.PositiveIntegerField(validators=[MaxValueValidator(4095)])
     name = models.CharField(max_length=256)
     comment = models.CharField(max_length=256, blank=True)
 
@@ -205,7 +206,7 @@ class Mx(models.Model):
     PRETTY_NAME = "Enregistrements MX"
 
     zone = models.ForeignKey('Extension', on_delete=models.PROTECT)
-    priority = models.IntegerField(unique=True)
+    priority = models.PositiveIntegerField(unique=True)
     name = models.OneToOneField('Domain', on_delete=models.PROTECT)
 
     @cached_property
@@ -512,13 +513,15 @@ class OuverturePort(models.Model):
     
     Les ports de la plage sont compris entre begin et en inclus. 
     Si begin == end alors on ne représente qu'un seul port.
+
+    On limite les ports entre 0 et 65535, tels que défini par la RFC
     """
     TCP = 'T'
     UDP = 'U'
     IN = 'I'
     OUT = 'O'
-    begin = models.IntegerField()
-    end = models.IntegerField()
+    begin = models.PositiveIntegerField(validators=[MaxValueValidator(65535)])
+    end = models.PositiveIntegerField(validators=[MaxValueValidator(65535)])
     port_list = models.ForeignKey('OuverturePortList', on_delete=models.CASCADE)
     protocole = models.CharField(
             max_length=1,
diff --git a/topologie/migrations/0031_auto_20171015_2033.py b/topologie/migrations/0031_auto_20171015_2033.py
new file mode 100644
index 00000000..674af6c6
--- /dev/null
+++ b/topologie/migrations/0031_auto_20171015_2033.py
@@ -0,0 +1,40 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.7 on 2017-10-15 18:33
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('topologie', '0030_auto_20171004_0235'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='port',
+            name='port',
+            field=models.PositiveIntegerField(),
+        ),
+        migrations.AlterField(
+            model_name='stack',
+            name='member_id_max',
+            field=models.PositiveIntegerField(),
+        ),
+        migrations.AlterField(
+            model_name='stack',
+            name='member_id_min',
+            field=models.PositiveIntegerField(),
+        ),
+        migrations.AlterField(
+            model_name='switch',
+            name='number',
+            field=models.PositiveIntegerField(),
+        ),
+        migrations.AlterField(
+            model_name='switch',
+            name='stack_member_id',
+            field=models.PositiveIntegerField(blank=True, null=True),
+        ),
+    ]
diff --git a/topologie/models.py b/topologie/models.py
index 086e0aff..66c8fe94 100644
--- a/topologie/models.py
+++ b/topologie/models.py
@@ -52,8 +52,8 @@ class Stack(models.Model):
     name = models.CharField(max_length=32, blank=True, null=True)
     stack_id = models.CharField(max_length=32, unique=True)
     details = models.CharField(max_length=255, blank=True, null=True)
-    member_id_min = models.IntegerField()
-    member_id_max = models.IntegerField()
+    member_id_min = models.PositiveIntegerField()
+    member_id_max = models.PositiveIntegerField()
 
     def __str__(self):
         return " ".join([self.name, self.stack_id])
@@ -90,7 +90,7 @@ class Switch(models.Model):
         on_delete=models.CASCADE
         )
     location = models.CharField(max_length=255)
-    number = models.IntegerField()
+    number = models.PositiveIntegerField()
     details = models.CharField(max_length=255, blank=True)
     stack = models.ForeignKey(
         Stack,
@@ -98,7 +98,7 @@ class Switch(models.Model):
         null=True,
         on_delete=models.SET_NULL
         )
-    stack_member_id = models.IntegerField(blank=True, null=True)
+    stack_member_id = models.PositiveIntegerField(blank=True, null=True)
 
     class Meta:
         unique_together = ('stack', 'stack_member_id')
@@ -146,7 +146,7 @@ class Port(models.Model):
         )
 
     switch = models.ForeignKey('Switch', related_name="ports")
-    port = models.IntegerField()
+    port = models.PositiveIntegerField()
     room = models.ForeignKey(
         'Room',
         on_delete=models.PROTECT,
diff --git a/users/migrations/0056_auto_20171015_2033.py b/users/migrations/0056_auto_20171015_2033.py
new file mode 100644
index 00000000..a47aca6a
--- /dev/null
+++ b/users/migrations/0056_auto_20171015_2033.py
@@ -0,0 +1,37 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.7 on 2017-10-15 18:33
+from __future__ import unicode_literals
+
+import django.core.validators
+from django.db import migrations, models
+import users.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('users', '0055_auto_20171003_0556'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='listright',
+            name='gid',
+            field=models.PositiveIntegerField(null=True, unique=True),
+        ),
+        migrations.AlterField(
+            model_name='listright',
+            name='listright',
+            field=models.CharField(max_length=255, unique=True, validators=[django.core.validators.RegexValidator('^[a-z]+$', message='Les groupes unix ne peuvent contenir            que des lettres minuscules')]),
+        ),
+        migrations.AlterField(
+            model_name='user',
+            name='rezo_rez_uid',
+            field=models.PositiveIntegerField(blank=True, null=True, unique=True),
+        ),
+        migrations.AlterField(
+            model_name='user',
+            name='uid_number',
+            field=models.PositiveIntegerField(default=users.models.User.auto_uid, unique=True),
+        ),
+    ]
diff --git a/users/models.py b/users/models.py
index 2f8f888f..550bc770 100644
--- a/users/models.py
+++ b/users/models.py
@@ -243,8 +243,8 @@ class User(AbstractBaseUser):
     state = models.IntegerField(choices=STATES, default=STATE_ACTIVE)
     registered = models.DateTimeField(auto_now_add=True)
     telephone = models.CharField(max_length=15, blank=True, null=True)
-    uid_number = models.IntegerField(default=auto_uid, unique=True)
-    rezo_rez_uid = models.IntegerField(unique=True, blank=True, null=True)
+    uid_number = models.PositiveIntegerField(default=auto_uid, unique=True)
+    rezo_rez_uid = models.PositiveIntegerField(unique=True, blank=True, null=True)
 
     USERNAME_FIELD = 'pseudo'
     REQUIRED_FIELDS = ['name', 'surname', 'email']
@@ -840,7 +840,7 @@ class ListRight(models.Model):
             que des lettres minuscules"
         )]
     )
-    gid = models.IntegerField(unique=True, null=True)
+    gid = models.PositiveIntegerField(unique=True, null=True)
     details = models.CharField(
         help_text="Description",
         max_length=255,