Filter a url

Hello,

I want to filter a url from $ENV{'HTTP_REFERER'}
If the url is http://www.testdomein.nl/test.html
I only want a result testdomein.nl

I have been testing whit this script
$url =~ s/.*?\.(.+?)\/.*?/$1/is;

It delets the first part of the url corect, but after .nl it deletes 
the slash and not the remaining tekst.
The result is testdomein.nltest.html

What is it i do wrong.

Thanks,
Eelco Alosery