diff --git a/modoboa_installer/config_dict_template.py b/modoboa_installer/config_dict_template.py
index 55d4580..490052e 100644
--- a/modoboa_installer/config_dict_template.py
+++ b/modoboa_installer/config_dict_template.py
@@ -30,6 +30,10 @@ ConfigDictTemplate = [
     {
         "name": "certificate",
         "values": [
+            {
+                "option": "generate",
+                "default": "true",
+            },
             {
                 "option": "type",
                 "default": "self-signed",
diff --git a/modoboa_installer/ssl.py b/modoboa_installer/ssl.py
index a4c61a7..6b61db5 100644
--- a/modoboa_installer/ssl.py
+++ b/modoboa_installer/ssl.py
@@ -148,6 +148,10 @@ class LetsEncryptCertificate(CertificateBackend):
 def get_backend(config):
     """Return the appropriate backend."""
     cert_type = config.get("certificate", "type")
+    condition = (not config.getboolean("certificate", "generate") and
+                 cert_type != "manual")
+    if condition:
+        return None
     if cert_type == "letsencrypt":
         return LetsEncryptCertificate(config)
     if cert_type == "manual":