diff --git a/modoboa/core/app_settings.py b/modoboa/core/app_settings.py
index 684138a36..0194ba035 100644
--- a/modoboa/core/app_settings.py
+++ b/modoboa/core/app_settings.py
@@ -202,7 +202,7 @@ class GeneralParametersForm(parameters.AdminParametersForm):
         tpl = self.cleaned_data["ldap_user_dn_template"]
         try:
             test = tpl % {"user": "toto"}
-        except ValueError:
+        except (KeyError, ValueError):
             raise forms.ValidationError(_("Invalid syntax"))
         return tpl
 
diff --git a/modoboa/extensions/postfix_autoreply/app_settings.py b/modoboa/extensions/postfix_autoreply/app_settings.py
index aba9535e3..464c226df 100644
--- a/modoboa/extensions/postfix_autoreply/app_settings.py
+++ b/modoboa/extensions/postfix_autoreply/app_settings.py
@@ -39,3 +39,16 @@ Best regards,
         ),
         widget=forms.widgets.Textarea
     )
+
+    def clean_default_content(self):
+        """Check if the provided value is valid.
+
+        Must be a valid format string which will be used with the %
+        operator.
+        """
+        tpl = self.cleaned_data["default_content"]
+        try:
+            test = tpl % {"name": "Antoine Nguyen"}
+        except (KeyError, ValueError):
+            raise forms.ValidationError(ugettext_lazy("Invalid syntax"))
+        return tpl
diff --git a/modoboa/extensions/postfix_autoreply/general_callbacks.py b/modoboa/extensions/postfix_autoreply/general_callbacks.py
index 86b89f9c1..2cf11a2b9 100644
--- a/modoboa/extensions/postfix_autoreply/general_callbacks.py
+++ b/modoboa/extensions/postfix_autoreply/general_callbacks.py
@@ -138,7 +138,8 @@ def save_extra_mailform_fields(form_name, mailbox, values):
     else:
         arm = ARmessage(mbox=mailbox)
         arm.subject = parameters.get_admin("DEFAULT_SUBJECT")
-        arm.content = parameters.get_admin("DEFAULT_CONTENT")
+        arm.content = parameters.get_admin("DEFAULT_CONTENT") \
+            % {'name': mailbox.user.fullname}
         arm.fromdate = timezone.now()
     arm.enabled = True if values['autoreply'] == 'yes' else False
     arm.save()