diff --git a/etc/inc/util.inc b/etc/inc/util.inc
index 8af4444c70..54dbafcef4 100644
--- a/etc/inc/util.inc
+++ b/etc/inc/util.inc
@@ -215,7 +215,7 @@ function is_validaliasname($name) {
 	if (in_array($name, $reserved, true))
 		return; /* return NULL */
 
-	if (!preg_match("/[^a-zA-Z0-9]/", $name))
+	if (!preg_match("/[^a-zA-Z0-9\-_]/", $name))
 		return true;
 	else
 		return false;
@@ -563,4 +563,4 @@ function mac_format($clientmac) {
     }
 }
 
-?>
\ No newline at end of file
+?>