|Note: Article about Proxmox VE 2.0 beta|
Proxmox VE supports multiple authentication sources, e.g. Microsoft Active Directory, LDAP, Linux PAM or the integrated Proxmox VE authentication server.
By using the role based user- and permission management for all objects (VM´s, storages, nodes, etc.) granular access can be defined.
Proxmox VE stores all user attributes in /etc/pve/users.cfg. So there must be an entry for each user in that file. The password is not stored, instead you can use the following methods to verify passwords.
Microsoft Active Directory
Linux PAM standard authentication
Proxmox VE authentication server
This is a unix like password store (/etc/pve/priv/shadow.cfg). Password are encrypted using the SHA-256 hash method. Users are allowed to change passwords.