.htaccess is your friend. You can setup allow deny, basic authentication, etc with an .htaccess file.
Thanks for the reply. I know about .htaccess and htpasswd. But I was wondering if I missed some nifty feature of ISPConfig that could make such a thing a little bit easier. It would be nice if you could limit access to ISPConfig defined site users from within ISPConfig itself and not having to do that manually.
Hmm, you probably could add the .htaccess to the site templates, then you just have to hack one of the ISPConfig files to create the password file part, or for that matter, point it to the .htpasswd in the sites root directory. (i.e. AuthUserFile /var/www/web1/.htpasswd) Look at the way the stats is setup, and copy that.
I'll definitly have a look. I'm quite a beginner though and and I'm still not comfortable with ISPConfig yet to start looking at and modifying templates. I'm not even sure which templates you mean I also prefer not to hack the sources. Once you start doing that, it will haunt you with every ISPConfig update.
Or you copy the .htaccess file from the /stats directory of the website to the website root directory (web).