I have a Centos server running apache, php, and pure-ftp.
I have 2 sites (domains) through apache, one of them wordpress and one of them drupal. I uploaded them using my ftp account as user "ftpuser" and group "ftpgroup". Apache is running as user "apache" and php the same (apache).
I have not changes the file permissions for anything, but I did realize that I needed to supply FTP credentials for both wordpress and drupal when downloading modules, which i didn’t have to do when I had everything set to 777 permissions (a long time ago, before I knew about permissions)
What user and groups should the files have. I know that directories should be 755 (or 775?) and files should be 644 (or 664?). But what user/groups should they be under?
In Your case, the user should be “apache”, but if You couldn’t make chown on files, probably, You will have to put 777 on some directories, as sites/default/files/ .