diff --git a/molecule/resources/inventory/host_vars/db/vars b/molecule/resources/inventory/host_vars/db/vars
index 0a4e0b1..5853f87 100644
--- a/molecule/resources/inventory/host_vars/db/vars
+++ b/molecule/resources/inventory/host_vars/db/vars
@@ -12,6 +12,7 @@ postgresql_connection:
   client_ip: "{{ web_vm.ip }}"
   client_certificate_filename: "/var/lib/pgsql/certs/root.crt" # required if using SSL, where to copy the client certificate to on the server
   listen_addresses: "'*'"
+  subnet_mask: 255.255.255.255
 
 # mirsg.ssl_certificates - postgresql server
 postgresql_ssl_certificate: