We have Posix ACLs set up on our webserver and everything works fine EXCEPT for file uploads from a web browser in which case the default ACL is not applied. Any reasons why this might be happening or suggestions?
I assume your ACLs are file system level restrictions. It's likely that your web server software is running as root or some other privaledged user and thus not hitting the ACLs you expect.
What do you need to limit that the php file upload restrictions don't match? That would be your first line of defense for file size or type restrictions.