I have a fairly default Apache install on Ubuntu 10.10. There's no virtual hosting and I would rather not add that. All domains that map to that machine are therefore served by the default site and the same directory.
What I would like is the .htaccess file in a specific directory to disallow access from a specific domain to that directory.
To clarify, xxx.foo.com/thefile.html gives a 403 (or whatever), but any other sub-domain or domain permits access to the file.