VSFTPD supports virtual users with PAM (pluggable authentication modules). A virtual user is a user login which does not exist as a real login on the system in /etc/passwd and /etc/shadow file. Virtual users can therefore be more secure than real users, because a compromised account can only use the FTP server but cannot login to system to use other services such as ssh or smtp.
Every IT shop has a mix of Windows and Linux system. Sometime you need to authenticate your Linux desktop system against Microsoft Active Directory service. You can save time, effort and IT infrastructure by sharing authentication server. This article explains how to setup the Linux desktop computers with Active Directory using Samba and winbind.
How do I lock out a user after a set number of login attempts in Linux but also automatically unlock it after N minutes?
su is used to become another user during a login session. Invoked without a username, su defaults to becoming the super user. The user will be prompted for a password, if appropriate. Invalid passwords will produce an error message. All attempts, both valid and invalid, are logged to detect abuses of the system. By default [...]
Under Linux password related utilities and config file(s) comes from shadow password suite. The /etc/login.defs file defines the site-specific configuration for this suite. This file is a readable text file, each line of the file describing one configuration parameter. The lines consist of a configuration name and value, separated by whitespace. You need to set [...]