The Pluggable Authentication Module (PAM) allows applications (in this case, Ingres) to authenticate users with a plug-in mechanism, as an alternative to the default authentication mechanism of a Linux or UNIX environment. Each plug-in is a shared library that is dynamically loaded into the PAM module.

PAM provides plug-ins for authentication at the operating system level or using third-party solutions, such as LDAP or Kerberos.

PAM allows applications such as Ingres to authenticate users transparently, regardless of the underlying authentication mechanism. Applications do not have to be recompiled or reconfigured if your authentication mechanism changes.