diff --git a/attributes.go b/attributes.go
index 7db0e23..de1ba77 100644
--- a/attributes.go
+++ b/attributes.go
@@ -171,6 +171,14 @@ func (t AttrType) String() string {
 	return s
 }
 
+// Known returns true if AttrType is known and implemented
+// by this library.
+func (t AttrType) Known() bool {
+	_, valid := attrNames()[t]
+
+	return valid
+}
+
 // RawAttribute is a Type-Length-Value (TLV) object that
 // can be added to a STUN message. Attributes are divided into two
 // types: comprehension-required and comprehension-optional.  STUN
diff --git a/attributes_test.go b/attributes_test.go
index a12a01d..5b229f9 100644
--- a/attributes_test.go
+++ b/attributes_test.go
@@ -107,3 +107,12 @@ func TestAttrTypeRange(t *testing.T) {
 		})
 	}
 }
+
+func TestAttrTypeKnown(t *testing.T) {
+	// All Attributes in attrNames should be known
+	for attr := range attrNames() {
+		assert.True(t, attr.Known())
+	}
+
+	assert.False(t, AttrType(0xFFFF).Known()) // Known
+}