diff --git a/roles/mail_server/molecule/default/group_vars/parameters-optional.yml b/roles/mail_server/molecule/default/group_vars/parameters-optional.yml
index 158e2d7022927475caab12730455f422fa4240c7..89fdffed8090b6ce448092721f1f3a7ce4d493f0 100644
--- a/roles/mail_server/molecule/default/group_vars/parameters-optional.yml
+++ b/roles/mail_server/molecule/default/group_vars/parameters-optional.yml
@@ -36,7 +36,7 @@ mail_server_smtp_additional_configuration: |
 
 # Variables dependant on distribution release.
 release_based_smtp_allow_relay_from:
-  buster: "192.168.56.20"
+  buster: "192.168.56.21"
 
 # common
 ca_certificates:
diff --git a/roles/mail_server/molecule/default/host_vars/ldap-server.yml b/roles/mail_server/molecule/default/host_vars/ldap-server.yml
index a8be5b51027c69abb5c5665b027c5f7ebdc5fc7d..58d7e2fa1950907b7d36d7195b64c474654dc39b 100644
--- a/roles/mail_server/molecule/default/host_vars/ldap-server.yml
+++ b/roles/mail_server/molecule/default/host_vars/ldap-server.yml
@@ -44,5 +44,5 @@ backup_host_ssh_private_keys:
 backup_clients:
 
   - server: parameters-optional-b64
-    ip: 192.168.56.31
+    ip: 192.168.56.32
     public_key: "{{ lookup('file', 'tests/data/ssh/parameters-optional.pub') }}"
diff --git a/roles/mail_server/molecule/default/molecule.yml b/roles/mail_server/molecule/default/molecule.yml
index 5066317717b44b46c3c10b3ec5eb12dee21a5bb2..459f5d17b188dd8cf1ba2d69c70a468f75997f90 100644
--- a/roles/mail_server/molecule/default/molecule.yml
+++ b/roles/mail_server/molecule/default/molecule.yml
@@ -25,7 +25,7 @@ platforms:
     cpus: 1
     interfaces:
       - auto_config: true
-        ip: 192.168.56.10
+        ip: 192.168.56.11
         network_name: private_network
         type: static
     config_options:
@@ -37,7 +37,7 @@ platforms:
     cpus: 1
     interfaces:
       - auto_config: true
-        ip: 192.168.56.11
+        ip: 192.168.56.12
         network_name: private_network
         type: static
 
@@ -52,7 +52,7 @@ platforms:
     cpus: 1
     interfaces:
       - auto_config: true
-        ip: 192.168.56.20
+        ip: 192.168.56.21
         network_name: private_network
         type: static
 
@@ -67,7 +67,7 @@ platforms:
     cpus: 1
     interfaces:
       - auto_config: true
-        ip: 192.168.56.21
+        ip: 192.168.56.22
         network_name: private_network
         type: static
 
@@ -80,7 +80,7 @@ platforms:
     cpus: 1
     interfaces:
       - auto_config: true
-        ip: 192.168.56.30
+        ip: 192.168.56.31
         network_name: private_network
         type: static
 
@@ -93,7 +93,7 @@ platforms:
     cpus: 1
     interfaces:
       - auto_config: true
-        ip: 192.168.56.31
+        ip: 192.168.56.32
         network_name: private_network
         type: static
 
diff --git a/roles/mail_server/molecule/default/prepare.yml b/roles/mail_server/molecule/default/prepare.yml
index 99275761b1b857e24d670563d484267349340ced..80068905ba876a6a7953e530cea802e4206367e7 100644
--- a/roles/mail_server/molecule/default/prepare.yml
+++ b/roles/mail_server/molecule/default/prepare.yml
@@ -187,12 +187,12 @@
         state: present
       with_dict:
         # Force mail servers to use local ClamAV database mirror.
-        192.168.56.10: "db.local.clamav.net database.clamav.net"
-        192.168.56.11: "ldap-server backup-server"
-        192.168.56.20: "client1 smtp-server-requiring-tls"
-        192.168.56.21: "client2 smtp-server-refusing-tls"
-        192.168.56.30: "parameters-mandatory parameters-mandatory-buster64"
-        192.168.56.31: "parameters-optional parameters-optional-buster64"
+        192.168.56.11: "db.local.clamav.net database.clamav.net"
+        192.168.56.12: "ldap-server backup-server"
+        192.168.56.21: "client1 smtp-server-requiring-tls"
+        192.168.56.22: "client2 smtp-server-refusing-tls"
+        192.168.56.31: "parameters-mandatory parameters-mandatory-buster64"
+        192.168.56.32: "parameters-optional parameters-optional-buster64"
 
 - hosts: client
   become: true