Yes, it won’t work with intranet site, because uses a resources of worldwide Google search engine. I looked for other variants for Joomla but couldn’t find yet.
I found a search module for Joomla that use Google search engine – and it seems to be working well with filenames. But it has some inconvenience with search results – they displayed at the same window of module. May be there are some other desicions from search engines for sites (Google, yandex, yahoo etc.).
Thanks for answer. If the standart Joomla search can’t render and find that text, may be You may advise some another module for search by filenames? Thank you.