URLField validator regex does not allow valid domain name

[posta07]

For internal urls that I would like to enter into an URLField, I found that the regex that the validator uses flags the url as incorrect even though it is a valid URL.

For exmaple, ​http://servername/context/context/etc/ is flagged as incorrect. After reviewing the regex that's being used, it appears it's expecting a .com or .biz or some kind of extension.

Here is the regex related to testing for the 'domain':

(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+[A-Z]{2,6}\.?

As you can see, it expects a period character in the domain name followed by a 2-6 character length extension.

[Russell Keith-Magee]

Duplicate of #9202.