diff --git a/roles/mail_server/molecule/default/prepare.yml b/roles/mail_server/molecule/default/prepare.yml
index 011685d4206f4dc5163cde258b41cc42ec4d6a20..fa5b9fb3c9d2cfdbc3ef1d85ac97e663136823f5 100644
--- a/roles/mail_server/molecule/default/prepare.yml
+++ b/roles/mail_server/molecule/default/prepare.yml
@@ -34,6 +34,14 @@
           fqdn: parameters-optional-stretch64
         - name: parameters-optional-stretch64_smtp
           fqdn: parameters-optional-stretch64
+        - name: parameters-mandatory-buster64_imap
+          fqdn: parameters-mandatory-buster64
+        - name: parameters-mandatory-buster64_smtp
+          fqdn: parameters-mandatory-buster64
+        - name: parameters-optional-buster64_imap
+          fqdn: parameters-optional-buster64
+        - name: parameters-optional-buster64_smtp
+          fqdn: parameters-optional-buster64
 
     - name: Set-up link to generated X.509 material
       file:
@@ -86,6 +94,26 @@
         10.31.127.32: "parameters-mandatory parameters-mandatory-stretch64"
         10.31.127.33: "parameters-optional parameters-optional-stretch64"
 
+- hosts: buster
+  become: true
+  tasks:
+
+    - name: Set-up the hosts file
+      lineinfile:
+        path: /etc/hosts
+        regexp: "^{{ item.key }}"
+        line: "{{ item.key }} {{ item.value }}"
+        owner: root
+        group: root
+        mode: 0644
+        state: present
+      with_dict:
+        10.31.127.10: "ldap-server backup-server"
+        10.31.127.20: "client1 smtp-server-requiring-tls"
+        10.31.127.21: "client2 smtp-server-refusing-tls"
+        10.31.127.30: "parameters-mandatory parameters-mandatory-buster64"
+        10.31.127.31: "parameters-optional parameters-optional-buster64"
+
 - hosts: client
   become: true
   tasks: