--- a/formencode/validators.py
+++ b/formencode/validators.py
@@ -1448,9 +1448,9 @@
         ^(http|https)://
         (?:[%:\w]*@)?                              # authenticator
         (?:                                        # ip or domain
-        (?P<ip>(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?))|
+        (?P<ip>(?:(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?))|(?:\[[0-9a-fA-F:]+\]))|
         (?P<domain>[a-z0-9][a-z0-9\-]{,62}\.)*     # subdomain
-        (?P<tld>[a-z]{2,63}|xn--[a-z0-9\-]{2,59})  # top level domain
+        (?P<tld>[a-z]{2,63}|xn--[a-z0-9\-]{2,59}|[a-z0-9]{1,63}|[a-z0-9][a-z0-9\-]{,61}[a-z0-9])  # top level domain
         )
         (?::[0-9]{1,5})?                           # port
         # files/delims/etc