The syntax of the /etc/pam.conf configuration file is as follows:
* The file is made up of a list of rules, 
* each rule is typically placed on a single line, but may be extended with an escaped end of line: `\<LF>'. \
* Comments are preceded with "#" marks and extend to the next end of line.

The format of each rule is a space separated collection of tokens, the first three being case-insensitive:
{{{
type control module module-arguments
}}}
Where:
* service - The services is the [*NIX] service like sshd.
* [type|PAM Service Types]
* [control|PAM Control]
* [module|PAM module|PAM Module Name]
* [module-arguments|PAM module-arguments]

!! Configuration File Structure
There are tow file structures in use.
* pam.conf - A single file that contains the configuration
* pam.d - A directory structure that has sub directories for each service.
The syntax of files contained in the /etc/pam.d/ directory, are identical except for the absence of any service field. In this case, the service is the name of the file in the /etc/pam.d/ directory. This filename must be in lower case.

An important feature of PAM, is that a number of rules may be stacked to combine the services of a number of PAMs for a given authentication task.

!! Service
The service is typically the familiar name of the corresponding application: login and su are good examples. The service-name, other, is reserved for giving default rules. Only lines that mention the current service (or in the absence of such, the other entries) will be associated with the given service-application.

The [PAM Service Types] is the management group that the rule corresponds to. It is used to specify which of the management groups the subsequent module is to be associated with. [Valid type entries|PAM Types|PAM Service Types]

!! More Information
There might be more information for this subject on one of the following:
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