Red Hat Linux 6
Oracle Database
I have a few questions regarding chmod command
https://www.computerhope.com/unix/uchmod.htm
Say for example, on one of my production server, I want to restrict access to a user to specific folders and files.
Please see below.

In screenshot above, the user test with group mtdnr should not access any folders shown above. I tried chmod 770 but still he can open folders. Or should I assign another group (for example group test with permission 700)?
[root@RH-FTTH-DEV-AP1 bin]# id test
uid=502(test) gid=501(mtdnr) groups=501(mtdnr)

Thanks
Joe