Chapter 27. Authentication Configuration
When a user logs in to a Red Hat Enterprise Linux system, the username and password
combination must be verified, or authenticated, as
a valid and active user. Sometimes the information to verify the user is
located on the local system, and other times the system defers the
authentication to a user database on a remote system.
The Authentication Configuration Tool provides a graphical interface
for configuring NIS, LDAP, and Hesiod to retrieve user information as well
as for configuring LDAP, Kerberos, and SMB as authentication protocols.
 | Note |
|---|
| | If you configured a medium or high security level during installation or
with the Security Level Configuration Tool,
network authentication methods, including NIS and LDAP, are not allowed
through the firewall.
|
This chapter does not explain each of the different authentication types
in detail. Instead, it explains how to use the
Authentication Configuration Tool to configure them. For more
information about the specific authentication types, refer to the
Red Hat Enterprise Linux Reference Guide.
To start the graphical version of the
Authentication Configuration Tool from the desktop, select the
(on the Panel) => => or
type the command system-config-authentication at a shell prompt
(for example, in an XTerm or a
GNOME terminal). To start the text-based
version, type the command authconfig as root
at a shell prompt.
 | Important |
|---|
| | After exiting the authentication program, the changes made take
effect immediately.
|
The User Information tab has several options. To
enable an option, click the empty checkbox beside it. To disable an
option, click the checkbox beside it to clear the checkbox. Click
OK to exit the program and apply the changes.
The following list explains what each option configures:
Enable NIS Support — Select this
option to configure the system as an NIS client which connects to
an NIS server for user and password authentication. Click the
Configure NIS button to specify the NIS
domain and NIS server. If the NIS server is not specified, the
daemon attempts to find it via broadcast.
The ypbind package must be installed for this
option to work. If NIS support is enabled, the
portmap and ypbind services
are started and are also enabled to start at boot time.
Enable LDAP Support — Select this
option to configure the system to retrieve user information via
LDAP. Click the Configure LDAP button to
specify the LDAP Search Base DN and
LDAP Server. If Use TLS to encrypt
connections is selected, Transport Layer Security is used
to encrypt passwords sent to the LDAP server.
The openldap-clients package must be
installed for this option to work.
For more information about LDAP, refer to the
Red Hat Enterprise Linux Reference Guide.
Enable Hesiod Support — Select this
option to configure the system to retrieve information from a remote
Hesiod database, including user information.
The hesiod package must be installed.
Winbind — Select this option to configure
the system to connect to a Windows Active Directory or a Windows domain
controller. User information can be accessed, as well as server authentication
options can be configured.
Cache User Information — Select this
option to enable the name service cache daemon
(nscd) and configure it to start at boot
time.
The nscd package must be installed for this
option to work.
