9
9.
The user enters the password.
10.
After receiving the login password, the HWTACACS client sends the HWTACACS server a
continue-authentication packet that includes the login password.
11.
If the authentication succeeds, the HWTACACS server sends back an authentication response to
indicate that the user has passed authentication.
12.
The HWTACACS client sends a user authorization request packet to the HWTACACS server.
13.
If the authorization succeeds, the HWTACACS server sends back an authorization response,
indicating that the user is now authorized.
14.
Knowing that the user is now authorized, the HWTACACS client pushes its CLI to the user and
permits the user to log in.
15.
The HWTACACS client sends a start-accounting request to the HWTACACS server.
16.
The HWTACACS server sends back an accounting response, indicating that it has received the
start-accounting request.
17.
The user logs off.
18.
The HWTACACS client sends a stop-accounting request to the HWTACACS server.
19.
The HWTACACS server sends back a stop-accounting response, indicating that the
stop-accounting request has been received.
LDAP
The Lightweight Directory Access Protocol (LDAP) provides standard multiplatform directory service. LDAP
was developed on the basis of the X.500 protocol. It improves the following functions of X.500:
•
Read/write interactive access.
•
Browse.
•
Search.
LDAP is suitable for storing data that does not often change. The protocol is used to store user information.
For example, LDAP server software Active Directory Server is used in Microsoft Windows operating
systems. The software stores the user information and user group information for user login authentication
and authorization.
LDAP directory service
LDAP uses directories to maintain the organization information, personnel information, and resource
information. The directories are organized in a tree structure and include entries. An entry is a set of
attributes with distinguished names (DNs). The attributes are used to store information such as usernames,
passwords, emails, computer names, and phone numbers.
LDAP uses a client/server model, and all directory information is stored in the LDAP server. Commonly
used LDAP server products include Microsoft Active Directory Server, IBM Tivoli Directory Server, and Sun
ONE Directory Server.
LDAP authentication and authorization
AAA can use LDAP to provide authentication and authorization services for users. LDAP defines a set of
operations to implement its functions. The main operations for authentication and authorization are the
bind operation and search operation.
•
The bind operation allows an LDAP client to perform the following tasks:
{
Establish a connection with the LDAP server.
