I disagree with the claim that root is always necessary to make cifs connections go. It is true, it is always needed for CLI smbmount, but a file manager such as nautilus has ability to mount a cifs share and it is not necessary to be root.
I don't use Gnome, but I still have Nautilus installed. Run this in a terminal to prevent having it try to take over the desktop
$ nautilus --no-desktop &
In Ubuntu 16.04, left side tree menu has "Connect to Server" on the bottom. Click that, the suggestion is type "smb://foo.example.com". smb is old word for "cifs", and if you put in your server and share with smb:// at beginning, connection does work! I promise. If your share is a named thing, it is required after a slash, "smb://foo.example.com/myshare".
I've used other file managers in same way. Protocol has to be "smb://".