diff --git a/uncloud_django_based/uncloud/uncloud_net/models.py b/uncloud_django_based/uncloud/uncloud_net/models.py
index 2eaf92d..734c9e9 100644
--- a/uncloud_django_based/uncloud/uncloud_net/models.py
+++ b/uncloud_django_based/uncloud/uncloud_net/models.py
@@ -1,4 +1,5 @@
 import uuid
+import ipaddress
 
 from django.db import models
 from django.contrib.auth import get_user_model
@@ -65,9 +66,13 @@ class VPNPool(UncloudModel):
         free_net = self.vpnnetworkreservation_set.objects.filter(vpnpool=self,
                                                                  status='free')
 
-        last_net = self.vpnnetworkreservation_set.objects.filter(vpnpool=self,
+        used_net = self.vpnnetworkreservation_set.objects.filter(vpnpool=self,
                                                                  status='used')
 
+        this_net = ipaddress.ip_network("{}/{}".format(
+            self.network, self.network_size))
+
+
         if num_free_networks == 0:
             raise Exception("No free networks")
 
@@ -84,10 +89,17 @@ class VPNPool(UncloudModel):
             next:
             """
 
-            last_ip = last_net.address
-#            next_ip =
+            last_net = ipaddress.ip_network(self.used_networks.last())
+            last_net_ip = last_net[0]
 
+            if last_net_ip.version == 6:
+                offset_to_next = 2**(128 - self.subnetwork_size)
+            elif last_net_ip.version == 4:
+                offset_to_next = 2**(32 - self.subnetwork_size)
 
+            next_net_ip = last_net_ip + offset_to_next
+
+            return next_net_ip