How to set up an LDAP server on CentOS 6

389 Directory Server

of 389 directory server Enterprise-class open source LDAP (Lightweight Directory Access Protocol) server for Linux developed by Red Hat. name “389” Derived from the LDAP default port number. On RHEL, 389 DS is called Red Hat Directory Server and is available as a paid subscription. The 389 directory is completely free and was developed by the Fedora community. Released under GPLv3 license.

The 389 server is built on Fedora but supports many operating systems such as CentOS, Scientific Linux, Debian, and Solaris.


  • Multi-master replication for fault tolerance and high write performance
  • Scalability: thousands of operations per second, tens of thousands of concurrent users, tens of millions of entries, hundreds of gigabytes of data
  • The code base has been continuously developed and deployed by the same team for over 10 years
  • Extensive documentation including helpful installation and deployment guides
  • Active Directory user and group synchronization
  • Secure authentication and transport (SSLv3, TLSv1, and SASL)
  • LDAPv3 support
  • Online, zero downtime, LDAP-based updates of schema, configuration, management, and access control information (ACI) in the tree
  • Graphical console for all aspects of user, group, and server management


1. Make sure the server is properly configured with a DNS server with the correct FQDN. invite This link Set the DNS server.

2. Configure the firewall to allow the server’s LDAP port. To do so, open the iptables configuration file and enter the lines as shown below. Changes made in the configuration file are shown in bold.

[[email protected] ~]# nano /etc/sysconfig/iptables
# Firewall configuration written by system-config-firewall
# Manual customization of this file is not recommended.
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
-A INPUT -m state --state NEW -m tcp -p tcp --dport 389 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 636 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 9830 -j ACCEPT

3. Restart iptables to save your changes.

[[email protected] ~]# service iptables restart

4. Add and install the EPEL repository and install the 389ds package.

[[email protected] ~]# wget

5. Before you begin installing and configuring the 389 directory server, you need to adjust server performance and security settings.

5.1. open /etc/sysctl.conf Create the file and add the lines as shown below. Changes made in the configuration file are shown in bold.

[[email protected] ~]# nano /etc/sysctl.conf
# Kernel sysctl configuration file for Red Hat Linux
# For binary values, 0 is disabled, 1 is enabled.  See sysctl(8) and
# sysctl.conf(5) for more details.
# Controls IP packet forwarding
net.ipv4.ip_forward = 0
# Controls source route verification
net.ipv4.conf.default.rp_filter = 1
# Do not accept source routing
net.ipv4.conf.default.accept_source_route = 0
# Controls the System Request debugging functionality of the kernel
kernel.sysrq = 0
# Controls whether core dumps will append the PID to the core filename.
# Useful for debugging multi-threaded applications.
kernel.core_uses_pid = 1
# Controls the use of TCP syncookies
net.ipv4.tcp_syncookies = 1
# Disable netfilter on bridges.
net.bridge.bridge-nf-call-ip6tables = 0
net.bridge.bridge-nf-call-iptables = 0
net.bridge.bridge-nf-call-arptables = 0
# Controls the default maxmimum size of a mesage queue
kernel.msgmnb = 65536
# Controls the maximum size of a message, in bytes
kernel.msgmax = 65536
# Controls the maximum shared segment size, in bytes
kernel.shmmax = 4294967295
# Controls the maximum number of shared memory segments, in pages
kernel.shmall = 268435456
net.ipv4.tcp_keepalive_time = 300
net.ipv4.ip_local_port_range = 1024 65000
fs.file-max = 64000

Review previous changes.

[[email protected] ~]# sysctl -p

Sample output:

net.ipv4.ip_forward = 0
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.default.accept_source_route = 0
kernel.sysrq = 0
kernel.core_uses_pid = 1
net.ipv4.tcp_syncookies = 1
error: "net.bridge.bridge-nf-call-ip6tables" is an unknown key
error: "net.bridge.bridge-nf-call-iptables" is an unknown key
error: "net.bridge.bridge-nf-call-arptables" is an unknown key
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.shmmax = 4294967295
kernel.shmall = 268435456
net.ipv4.tcp_keepalive_time = 300
net.ipv4.ip_local_port_range = 1024 65000
fs.file-max = 64000

5.2. Edit file descriptor /etc/security/limits.conf Add a line to the end of the file as shown below. Changes made in the configuration file are shown in bold.

[[email protected] ~]# nano /etc/security/limits.conf
# /etc/security/limits.conf
#Each line describes a limit for a user in the form:
# can be:
#        - an user name
#        - a group name, with @group syntax
#        - the wildcard *, for default entry
#        - the wildcard %, can be also used with %group syntax,
#                 for maxlogin limit
# can have the two values:
#        - "soft" for enforcing the soft limits
#        - "hard" for enforcing hard limits
# can be one of the following:
#        - core - limits the core file size (KB)
#        - data - max data size (KB)
#        - fsize - maximum filesize (KB)
#        - memlock - max locked-in-memory address space (KB)
#        - nofile - max number of open files
#        - rss - max resident set size (KB)
#        - stack - max stack size (KB)
#        - cpu - max CPU time (MIN)
#        - nproc - max number of processes
#        - as - address space limit (KB)
#        - maxlogins - max number of logins for this user
#        - maxsyslogins - max number of logins on the system
#        - priority - the priority to run user process with
#        - locks - max number of file locks the user can hold
#        - sigpending - max number of pending signals
#        - msgqueue - max memory used by POSIX message queues (bytes)
#        - nice - max nice priority allowed to raise to values: [-20, 19]
#        - rtprio - max realtime priority
#*               soft    core            0
#*               hard    rss             10000
#@student        hard    nproc           20
#@faculty        soft    nproc           20
#@faculty        hard    nproc           50
#ftp             hard    nproc           0
#@student        -       maxlogins       4
# End of file

5.3. open / etc / profile Create the file and add the lines as shown below. Changes are shown in bold.

[[email protected] ~]# nano /etc/profile
# /etc/profile
# System wide environment and startup programs, for login setup
# Functions and aliases go in /etc/bashrc
# It's NOT a good idea to change this file unless you know what you
# are doing. It's much better to create a shell script in
# /etc/profile.d/ to make custom changes to your environment, as this
# will prevent the need for merging in future updates.
pathmunge () {
    case ":${PATH}:" in
            if [ "$2" = "after" ] ; then

if [ -x /usr/bin/id ]; then
    if [ -z "$EUID" ]; then
        # ksh workaround
        EUID=`id -u`
        UID=`id -ru`
    USER="`id -un`"
# Path manipulation
if [ "$EUID" = "0" ]; then
    pathmunge /sbin
    pathmunge /usr/sbin
    pathmunge /usr/local/sbin
    pathmunge /usr/local/sbin after
    pathmunge /usr/sbin after
    pathmunge /sbin after
HOSTNAME=`/bin/hostname 2>/dev/null`
if [ "$HISTCONTROL" = "ignorespace" ] ; then
    export HISTCONTROL=ignoreboth
    export HISTCONTROL=ignoredups
# By default, we want umask to get set. This sets it for login shell
# Current threshold for system reserved uid/gids is 200
# You could check uidgid reservation validity in
# /usr/share/doc/setup-*/uidgid file
if [ $UID -gt 199 ] && [ "`id -gn`" = "`id -un`" ]; then
    umask 002
    umask 022
for i in /etc/profile.d/*.sh ; do
    if [ -r "$i" ]; then
        if [ "${-#*i}" != "$-" ]; then
            . "$i"
            . "$i" >/dev/null 2>&1
unset i
unset pathmunge

5.4. Add the following line to the end /etc/pam.d/login The files shown below. Changes made in the configuration file are shown in bold.

[[email protected] ~]# nano /etc/pam.d/login
auth [user_unknown=ignore success=ok ignore=ignore default=bad]
auth       include      system-auth
account    required
account    include      system-auth
password   include      system-auth
# close should be the first session rule
session    required close
session    required
session    optional
# open should only be followed by sessions to be executed in the user context
session    required open
session    required
session    optional force revoke
session    include      system-auth
-session   optional
session    required     /lib/security/

Add a user named 6. Fedora-DS.

[[email protected] ~]# useradd fedora-ds

Set a password for the new user.

[[email protected] ~]# passwd fedora-ds
Changing password for user fedora-ds.
New password: 
BAD PASSWORD: it is based on a dictionary word
Retype new password: 
passwd: all authentication tokens updated successfully.

Install LDAP server

[[email protected] ~]# yum install 389-ds openldap-clients -y

389 Directory server configuration

[[email protected] ~]#

Sample output:

This program will set up the 389 Directory and Administration Servers.
It is recommended that you have "root" privilege to set up the software.
Tips for using this program:
  - Press "Enter" to choose the default and go to the next screen
  - Type "Control-B" then "Enter" to go back to the previous screen
  - Type "Control-C" to cancel the setup program
Would you like to continue with set up? [yes]:  ##press enter##
Your system has been scanned for potential problems, missing patches,
etc.  The following output is a report of the items found that need to
be addressed before running this software in a production
389 Directory Server system tuning analysis version 10-AUGUST-2007.
NOTICE : System is i686-unknown-linux2.6.32-279.el6.i686 (1 processor).
WARNING: 622MB of physical memory is available on the system. 1024MB is recommended for best performance on large production system.
WARNING: There are only 1024 file descriptors (soft limit) available, which
limit the number of simultaneous connections.  
WARNING  : The warning messages above should be reviewed before proceeding.
Would you like to continue? [no]: yes ##type yes and press enter##
Choose a setup type:
   1. Express
       Allows you to quickly set up the servers using the most
       common options and pre-defined defaults. Useful for quick
       evaluation of the products.
   2. Typical
       Allows you to specify common defaults and options.
   3. Custom
       Allows you to specify more advanced options. This is 
       recommended for experienced server administrators only.
To accept the default shown in brackets, press the Enter key.
Choose a setup type [2]: 2 ##type 2 and press enter##
Enter the fully qualified domain name of the computer
on which you're setting up server software. Using the form
To accept the default shown in brackets, press the Enter key.
Warning: This step may take a few minutes if your DNS servers
can not be reached or if DNS is not configured correctly.  If
you would rather not wait, hit Ctrl-C and run this program again
with the following command line option to specify the hostname:
Computer name []:  ##press enter##
The servers must run as a specific user in a specific group.
It is strongly recommended that this user should have no privileges
on the computer (i.e. a non-root user).  The setup procedure
will give this user/group some permissions in specific paths/files
to perform server-specific operations.
If you have not yet created a user and group for the servers,
create this user and group using your native operating
system utilities.
System User [nobody]: fedora-ds ##input your yourname which you created earlier and press enter##
System Group [nobody]: fedora-ds
Server information is stored in the configuration directory server.
This information is used by the console and administration server to
configure and manage your servers.  If you have already set up a
configuration directory server, you should register any servers you
set up or create with the configuration server.  To do so, the
following information about the configuration server is required: the
fully qualified host name of the form
.(e.g., the port number
(default 389), the suffix, the DN and password of a user having
permission to write the configuration information, usually the
configuration directory administrator, and if you are using security
(TLS/SSL).  If you are using TLS/SSL, specify the TLS/SSL (LDAPS) port
number (default 636) instead of the regular LDAP port number, and
provide the CA certificate (in PEM/ASCII format).
If you do not yet have a configuration directory server, enter 'No' to
be prompted to set up one.
Do you want to register this software with an existing
configuration directory server? [no]:  ##press enter##
Please enter the administrator ID for the configuration directory
server.  This is the ID typically used to log in to the console.  You
will also be prompted for the password.
Configuration directory server
administrator ID [admin]:  ##enter the password and press enter##
Password (confirm): 
The information stored in the configuration directory server can be
separated into different Administration Domains.  If you are managing
multiple software releases at the same time, or managing information
about multiple domains, you may use the Administration Domain to keep
them separate.
If you are not using administrative domains, press Enter to select the
default.  Otherwise, enter some descriptive, unique name for the
administration domain, such as the name of the organization
responsible for managing the domain.
Administration Domain []:  ##press enter##
The standard directory server network port number is 389.  However, if
you are not logged as the superuser, or port 389 is in use, the
default value will be a random unused port number greater than 1024.
If you want to use port 389, make sure that you are logged in as the
superuser, that port 389 is not in use.
Directory server network port [389]:  ##press enter##
Each instance of a directory server requires a unique identifier.
This identifier is used to name the various
instance specific files and directories in the file system,
as well as for other uses as a server instance identifier.
Directory server identifier [server]:  ##press enter##
The suffix is the root of your directory tree.  The suffix must be a valid DN.
It is recommended that you use the dc=domaincomponent suffix convention.
For example, if your domain is,
you should use dc=example,dc=com for your suffix.
Setup will create this initial suffix for you,
but you may have more than one suffix.
Use the directory server utilities to create additional suffixes.
Suffix [dc=ostechnix, dc=com]:  ##press enter##
Certain directory server operations require an administrative user.
This user is referred to as the Directory Manager and typically has a
bind Distinguished Name (DN) of cn=Directory Manager.
You will also be prompted for the password for this user.  The password must
be at least 8 characters long, and contain no spaces.
Press Control-B or type the word "back", then Enter to back up and start over.
Directory Manager DN [cn=Directory Manager]:  ##press enter##
Password (confirm): 
The Administration Server is separate from any of your web or application
servers since it listens to a different port and access to it is
Pick a port number between 1024 and 65535 to run your Administration
Server on. You should NOT use a port number which you plan to
run a web or application server on, rather, select a number which you
will remember and which will not be used for anything else.
Administration port [9830]:  ##press enter##
The interactive phase is complete.  The script will now set up your
servers.  Enter No or go Back if you want to change something.
Are you ready to set up your servers? [yes]: 
Creating directory server . . .
Your new DS instance 'server' was successfully created.
Creating the configuration directory server . . .
Beginning Admin Server creation . . .
Creating Admin Server files and directories . . .
Updating adm.conf . . .
Updating admpw . . .
Registering admin server with the configuration directory server . . .
Updating adm.conf with information from configuration directory server . . .
Updating the configuration for the httpd engine . . .
Starting admin server . . .
output: Starting dirsrv-admin: 
output:                                                    [  OK  ]
The admin server was successfully started.
Admin server was successfully created, configured, and started.
Exiting . . .
Log file is '/tmp/setupkmf7gF.log'

Test the LDAP server

[[email protected] ~]# ldapsearch -x -b "dc=ostechnix,dc=com"
# extended LDIF
# LDAPv3
# base  with scope subtree
# filter: (objectclass=*)
# requesting: ALL
dn: dc=ostechnix,dc=com
objectClass: top
objectClass: domain
dc: ostechnix
# Directory Administrators,
dn: cn=Directory Administrators,dc=ostechnix,dc=com
objectClass: top
objectClass: groupofuniquenames
cn: Directory Administrators
uniqueMember: cn=Directory Manager
# Groups,
dn: ou=Groups,dc=ostechnix,dc=com
objectClass: top
objectClass: organizationalunit
ou: Groups
# People,
dn: ou=People,dc=ostechnix,dc=com
objectClass: top
objectClass: organizationalunit
ou: People
# Special Users,
dn: ou=Special Users,dc=ostechnix,dc=com
objectClass: top
objectClass: organizationalUnit
ou: Special Users
description: Special Administrative Accounts
# Accounting Managers, Groups,
dn: cn=Accounting Managers,ou=Groups,dc=ostechnix,dc=com
objectClass: top
objectClass: groupOfUniqueNames
cn: Accounting Managers
ou: groups
description: People who can manage accounting entries
uniqueMember: cn=Directory Manager
# HR Managers, Groups,
dn: cn=HR Managers,ou=Groups,dc=ostechnix,dc=com
objectClass: top
objectClass: groupOfUniqueNames
cn: HR Managers
ou: groups
description: People who can manage HR entries
uniqueMember: cn=Directory Manager
# QA Managers, Groups,
dn: cn=QA Managers,ou=Groups,dc=ostechnix,dc=com
objectClass: top
objectClass: groupOfUniqueNames
cn: QA Managers
ou: groups
description: People who can manage QA entries
uniqueMember: cn=Directory Manager
# PD Managers, Groups,
dn: cn=PD Managers,ou=Groups,dc=ostechnix,dc=com
objectClass: top
objectClass: groupOfUniqueNames
cn: PD Managers
ou: groups
description: People who can manage engineer entries
uniqueMember: cn=Directory Manager
# search result
search: 2
result: 0 Success
# numResponses: 10
# numEntries: 9

If you get Search: 2 Complete with any of the above results.

Make the LDAP server start automatically each time it restarts.

[[email protected]erver ~]# chkconfig dirsrv on

that’s it. Your LDAP server is ready to use.