This authentication method operates similarly to
password except that it uses PAM (Pluggable
Authentication Modules) as the authentication mechanism. The
default PAM service name is postgresql.
PAM is used only to validate user name/password pairs and optionally the
connected remote host name or IP address. Therefore the user must already
exist in the database before PAM can be used for authentication. For more
information about PAM, please read the
Linux-PAM Page.
The following configuration options are supported for PAM:
pamservicePAM service name.
pam_use_hostname
Determines whether the remote IP address or the host name is provided
to PAM modules through the PAM_RHOST item. By
default, the IP address is used. Set this option to 1 to use the
resolved host name instead. Host name resolution can lead to login
delays. (Most PAM configurations don't use this information, so it is
only necessary to consider this setting if a PAM configuration was
specifically created to make use of it.)
If PAM is set up to read /etc/shadow, authentication
will fail because the PostgreSQL server is started by a non-root
user. However, this is not an issue when PAM is configured to use
LDAP or other authentication methods.