Update validators.py

Updated DNSValidator regex

netbox/ipam/validators.py

@@ -24,7 +24,7 @@ class MinPrefixLengthValidator(BaseValidator):
 
 
 DNSValidator = RegexValidator(
-    regex='^[0-9A-Za-z*._-]+$',
+    regex=r'^([0-9A-Za-z_-]+|\*)(\.[0-9A-Za-z_-]+)*\.?$',
     message='Only alphanumeric characters, asterisks, hyphens, periods, and underscores are allowed in DNS names',
     code='invalid'
 )