FTP/SFTP Server Setup

Hello all,

I originally posted to linux4noobs but told I would bet a better answer here.

I am running Ubuntu 12.04 x64 and I am looking to use it as a replacement for our FileZilla FTP server running on Server 2003 on an old power hungry Dell PE2900. The box that Ubuntu is installed on is a H Microserver with 4gb and the DualCore AMS processor.

I want to setup a FTP server that allows for multiple users to access a single root FTP directory, such as /srv/ftp/shared. The caveat is that I am looking to provide certain users read/write and other users just read access based on there role in the organization.

I am a Windows Admin and I would normally just be able to set up Security Groups and apply NTFS permissions for what I want to accomplish, but I am not sure how I can accomplish this on Ubuntu. I want to use this as a learning experience.

If it can auth of my current AD domain that would be even better, but one step at a time.

Thank you all.

Edit: So I have been trying some of the suggestions below and have created a group called ftpshared and a user called ftpuser. I have added ftpuser to the ftpshared group.

I modified the /etc/ssh/sshd_config, commented out Subsystem sftp /usr/lib/openssh/sftp-server and added the following to the bottom of the sshd_config file:

Subsytem sftp internal-sftp Match Group ftpshared ChrootDirectory /srv/ftp/shared ForceCommand internal-sftp X11Forwarding no AllowTCPForwarding no 

I then did chmod 1775 /srv/ftp/shared and chown root:ftpshared /srv/ftp/shared

Now when I goto login from say FileZilla I get a network connection error and looking at /var/log/auth.log I see numerous, fatal: bad ownership or modes for chroot directory /srv/ftp/shared.

How do I resolve this now? Doing some research show I need to make the permissions 755 on the /srv/ftp/shared but that would not allow for what I am trying to do.

Any other suggestions? Thanks a bunch.