diff --git a/management/univention-directory-manager-modules/modules/univention/admin/syntax.py b/management/univention-directory-manager-modules/modules/univention/admin/syntax.py
index 4327776846..92fd796588 100644
--- a/management/univention-directory-manager-modules/modules/univention/admin/syntax.py
+++ b/management/univention-directory-manager-modules/modules/univention/admin/syntax.py
@@ -1883,7 +1883,7 @@ class dnsHostname(dnsName):
 	valueError: A host name or FQDN must start and end with a letter or number. In between additionally dashes, dots and underscores are allowed.
 	"""
 
-	LABEL = re.compile(r'^(?![0-9]+$|[_-])[a-zA-Z0-9_-]{1,63}(?<![_-])$')
+	LABEL = re.compile(r'^[a-zA-Z0-9][a-zA-Z0-9_-]{0,63}(?<![_-])$')
 	NUMERIC = re.compile(r'^[0-9.]+$')
 
 	@classmethod
@@ -1922,7 +1922,7 @@ class dnsName_umlauts(simple):
 
 	min_length = 1
 	max_length = 63
-	regex = re.compile(r"^(?![0-9]+$|[_-])[\w_-]{1,63}(?<![_-])$", re.UNICODE)
+	regex = re.compile(r"^[\w][\w_-]{0,63}(?<![_-])$", re.UNICODE)
 	error_message = _(
 		"A host name or FQDN must start and end with a letter or number. In between additionally dashes, dots "
 		"and underscores are allowed."