Bind rules identify a set of users by using the following methods:
The users, groups, and roles that are granted access.
The location from which an entity must bind. The location from which a user authenticates can be spoofed and cannot be trusted. Do not base ACIs on this information alone.
The time or day on which binding must occur.
The type of authentication that must be in use during binding.
A simple bind rule might require a person accessing the directory to belong to a specific group. A complex bind rule can require a person to belong to a specific group and to log in from a machine with a specific IP address, between 8 am and 5 pm. Additionally, bind rules can be complex constructions that combine these criteria by using Boolean operators.
The server evaluates the logical expressions used in ACIs according to a three-valued logic, similar to the one used to evaluate LDAP filters, as described in section 188.8.131.52 of RFC 4511 Lightweight Directory Access Protocol (v3). Therefore, if any component in the expression evaluates to Undefined (for example if the evaluation of the expression aborted due to a resource limitation), then the server handles this case correctly. The server does not erroneously grant access because an Undefined value occurred in a complex Boolean expression.