diff --git a/libguh/types/paramtype.cpp b/libguh/types/paramtype.cpp
index 595c0f74..9a88f94e 100644
--- a/libguh/types/paramtype.cpp
+++ b/libguh/types/paramtype.cpp
@@ -86,6 +86,16 @@ void ParamType::setLimits(const QVariant &min, const QVariant &max)
     m_maxValue = max;
 }
 
+QList<QVariant> ParamType::allowedValues() const
+{
+    return m_allowedValues;
+}
+
+void ParamType::setAllowedValues(const QList<QVariant> allowedValues)
+{
+    m_allowedValues = allowedValues;
+}
+
 QDebug operator<<(QDebug dbg, const ParamType &paramType)
 {
     dbg.nospace() << "ParamType(Name: " << paramType.name()
diff --git a/libguh/types/paramtype.h b/libguh/types/paramtype.h
index bf7811a2..bf361b59 100644
--- a/libguh/types/paramtype.h
+++ b/libguh/types/paramtype.h
@@ -45,12 +45,16 @@ public:
     QPair<QVariant, QVariant> limits() const;
     void setLimits(const QVariant &min, const QVariant &max);
 
+    QList<QVariant> allowedValues() const;
+    void setAllowedValues(const QList<QVariant> allowedValues);
+
 private:
     QString m_name;
     QVariant::Type m_type;
     QVariant m_defaultValue;
     QVariant m_minValue;
     QVariant m_maxValue;
+    QVariantList m_allowedValues;
 };
 
 QDebug operator<<(QDebug dbg, const ParamType &paramType);
diff --git a/plugins/deviceplugins/mailnotification/devicepluginmailnotification.cpp b/plugins/deviceplugins/mailnotification/devicepluginmailnotification.cpp
index 755d2c0f..a99ac977 100644
--- a/plugins/deviceplugins/mailnotification/devicepluginmailnotification.cpp
+++ b/plugins/deviceplugins/mailnotification/devicepluginmailnotification.cpp
@@ -322,6 +322,7 @@ QList<DeviceClass> DevicePluginMailNotification::supportedDevices() const
     customMailParams.append(portCustomParam);
 
     ParamType authCustomParam("auth", QVariant::String);
+    authCustomParam.setAllowedValues(QVariantList() << "PLAIN" << "LOGIN");
     customMailParams.append(authCustomParam);
 
     deviceClassCustomMail.setActions(mailActions);
diff --git a/server/jsonrpc/jsontypes.cpp b/server/jsonrpc/jsontypes.cpp
index 4056a7a2..9a95bb40 100644
--- a/server/jsonrpc/jsontypes.cpp
+++ b/server/jsonrpc/jsontypes.cpp
@@ -69,6 +69,7 @@ void JsonTypes::init()
     s_paramType.insert("o:defaultValue", "variant");
     s_paramType.insert("o:minValue", "variant");
     s_paramType.insert("o:maxValue", "variant");
+    s_paramType.insert("o:allowedValues", QVariantList() << "variant");
 
     // Param
     s_param.insert("name", "string");
@@ -332,6 +333,9 @@ QVariantMap JsonTypes::packParamType(const ParamType &paramType)
     if (paramType.maxValue().isValid()) {
         variantMap.insert("maxValue", paramType.maxValue());
     }
+    if (!paramType.allowedValues().isEmpty()) {
+        variantMap.insert("allowedValues", paramType.allowedValues());
+    }
     return variantMap;
 }