diff --git a/lam/lib/account.inc b/lam/lib/account.inc
index 3995c7fc..f264f27a 100644
--- a/lam/lib/account.inc
+++ b/lam/lib/account.inc
@@ -452,7 +452,7 @@ function get_preg($argument, $regexp) {
 					$pregexpr = '/^([[:alnum:]\\ \\|\\#\\*\\,\\.\\;\\:\\_\\+\\!\\%\\&\\/\\?\\{\\(\\)\\}-])*$/u';
 					break;
 		case 'cn':	// first character must be a letter. All letters, numbers, space and @._- are allowed characters
-					$pregexpr = '/^[[:alpha:]]([[:alnum:]@\\.\\ \\_-])*$/u';
+					$pregexpr = '/^[[:alpha:]]([[:alnum:]@\\.\\ \\_-])*(\\$)?$/u';
 					break;
 		case 'groupname':	// first character must be a letter. All letters, numbers, space and ._- are allowed characters
 		case 'username':	// first character must be a letter. All letters, numbers, space and ._- are allowed characters