# OpenAM Administration Guide
Chapter 2. Defining Authentication Services

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## 2.2. Configuring Authentication Modules

The OpenAM console provides two places where the OpenAM administrator can configure authentication modules.

1. Under Configuration > Authentication, you configure available modules for use throughout OpenAM. What you set up here is inherited for use elsewhere.

2. Under Access Control > `Realm Name` > Authentication, you configure modules for your realm. What you set up at this level inherits from the global configuration, but you can override what is inherited. You can also add your own modules if necessary.

The configuration of individual modules depend on its function. The configuration of an Active Directory over LDAP user authentication module requires connection information and details about where to search for users. In contrast, the configuration of the HOTP module for OTP authentication requires data about the password length and the mail server or SMS gateway for to send the password during authentication.