diff --git a/roles/aurore-firewall/templates/firewall_config.py b/roles/aurore-firewall/templates/firewall_config.py
index d782cdb..052c6d2 100644
--- a/roles/aurore-firewall/templates/firewall_config.py
+++ b/roles/aurore-firewall/templates/firewall_config.py
@@ -58,7 +58,7 @@ nat = [
         },
         'ip_sources' : '10.{{ subnet_ids.users_wired }}.0.0/16',
         'extra_nat' : {
-            '10.129.{{ apartment_block_id }}.240' : '45.66.108.25{{ apartment_block_id }}'
+            '10.129.{{ apartment_block_id }}.{{ '1' if "backup" in inventory_hostname else '2' }}40' : '45.66.108.25{{ apartment_block_id }}'
         }
     }
 ]