CentOS: Install OpenLDAP with Webmin – The Simple Way

Installing OpenLDAP with Webmin will require a lot of steps. I have created a BASH script to install OpenLDAP with Webmin in CentOS 6 servers. To install, simply download the installer script at here:

Installation example will be as below. I am using a freshly installed CentOS 6.3 64bit installed with minimal ISO, with wget and perl installed.

1. Download and extract the installer script:

$ cd /usr/local/src
$ wget http://blog.secaserver.com/files/openldap_installer.sh

2. Change the permission to 755:

$ chmod 755 openldap_installer.sh

3. Execute the script and follow the wizard as example below:

$ ./openldap_installer.sh
           This script will install OpenLDAP
It assumes that there is no OpenLDAP installed in this host
   SElinux will be disabled and firewall will be stopped
What is the root domain? [eg mydomain.com]: majimbu.net
What is the administrator domain? [eg ldap.majimbu.net or manager.majimbu.net]: ldap.majimbu.net
What is the administrator password that you want to use?: MyN23pQ
Do you want to install Webmin/Do you want me to configure your Webmin LDAP modules? [Y/n]: Y

You should see the installation process output as below:

Kindly review following details before proceed with installation:
Hostname: ldap.majimbu.net
Root DN: dc=majimbu,dc=net
Administrator DN: cn=ldap,dc=majimbu,dc=net
Administrator Password: MyN23pQ
Webmin installation: Y
Can I proceed with the installation? [Y/n]: Y
Checking whether openldap-servers has been installed..
openldap-servers package not found. Proceed with installation
Disabling SElinux and stopping firewall..
iptables: Flushing firewall rules:                                 [ OK ]
iptables: Setting chains to policy ACCEPT: filter                  [ OK ]
iptables: Unloading modules:                                       [ OK ]
Installing OpenLDAP using yum..
Package cronie-1.4.4-7.el6.x86_64 already installed and latest version
Package sudo-1.7.4p5-13.el6_3.x86_64 already installed and latest version
OpenLDAP installed
Configuring OpenLDAP database..
Configuring monitoring privileges..
Configuring database cache..
Generating SSL..
Generating a 2048 bit RSA private key
writing new private key to '/etc/openldap/certs/majimbu_key.pem'
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
Country Name (2 letter code) [XX]:MY
State or Province Name (full name) []:Kuala Lumpur
Locality Name (eg, city) [Default City]:Bukit Bintang
Organization Name (eg, company) [Default Company Ltd]:Majimbu Net Corp
Organizational Unit Name (eg, section) []:IT
Common Name (eg, your name or your server's hostname) []:ldap.majimbu.net
Email Address []:[email protected]
Configuring LDAP service..
Checking OpenLDAP configuration..
config file testing succeeded
OpenLDAP installation done. Starting SLAPD..
Starting slapd:                                                    [ OK ]
Configuring LDAP client inside this host..
Checking the Webmin installation..
Webmin package not found in this host. Installing Webmin..
Retrieving http://www.webmin.com/download/rpm/webmin-current.rpm
warning: /var/tmp/rpm-tmp.XmXunn: Header V3 DSA/SHA1 Signature, key ID 11f63c51: NOKEY
Preparing... ########################################### [100%]
Operating system is CentOS Linux
    1:webmin ########################################### [100%]
Webmin install complete. You can now login to http://ldap.majimbu.net:10000/
as root with your root password.
Webmin installed.
Configuring webmin LDAP server module..
Configuring webmin LDAP client module..
Installation completed! [ OK ]
    You may need to open following port in firewall: 389, 636, 10000
Dont forget to refresh your Webmin module! Login to Webmin > Refresh Modules


4. Installation done. We need to refresh the Webmin module from the Webmin page. Login into Webmin > Refresh Modules:



5. You need to refresh again the Webmin page so the activated module will be listed in the side menu as screen shot below:


You can now start to create your LDAP object using your Webmin modules Webmin > Servers > LDAP Server To add port exception into firewall rules, you can use following command:

$ iptables -I INPUT -m tcp -p tcp --dport 389 -j ACCEPT
$ iptables -I INPUT -m tcp -p tcp --dport 636 -j ACCEPT
$ iptables -I INPUT -m tcp -p tcp --dport 10000 -j ACCEPT

Clone VM in VMware ESXi 5 using vSphere Client

I am a free VMware ESXi user. Cloning VM is no way to be as easy as VMware Workstation or vCenter. As you know, for free user, you can only manage your ESXi host directly using vSphere client. Cloning will save your time tremendously when you want to have several machines with same configuration inside one host.

I will be cloning a VM which run under CentOS 6.3 64bit platform with VMtools installed and using following details:

ESXi version: VMware ESXi 5.0.0 build 768111
ESXi host:
Main VM name: CentOS-Test
Main VM IP:
Cloned VM name: CentOS-Clone1
Cloned VM IP:

1. We will use SSH to do cloning. You can enable SSH service (if disabled) by using vSphere client and connect to your ESXi host. Go to Configuration > Security Profile > Services > Properties > select SSH > Options > Start as refer to screen shot below:



2. Create the cloned VM using similar specification with the main VM. There is one different thing here that we DO NOT need to create the disk for this cloned VM because we will use the clone virtual hard disk which we will create in step #3:



3. Now we need to clone the disk from main VM to the cloned VM directory. Connect to ESXi host using SSH and run following command:

~ # vmkfstools -i /vmfs/volumes/datastore1/CentOS-Test/CentOS-Test.vmdk /vmfs/volumes/datastore1/CentOS-Clone1/CentOS-Clone1.vmdk
Destination disk format: VMFS zeroedthick
Cloning disk '/vmfs/volumes/datastore1/CentOS-Test/CentOS-Test.vmdk'...
Clone: 100% done.

4. Once done, we will need to add the virtual hard disk into cloned VM using vSphere client. Edit the VM Properties > Add > Hard Disk > Use an existing virtual disk > locate the hard disk as screenshot below > Next > Next > Finish.




5. You will then should have the virtual machine properties summary as below:



6. Start the cloned virtual machine. Once you login into CentOS, you will realized that the network interface will be converted into eth1:


We need to run following command and restart the CentOS box to bring back the eth0 as this is actually the nature of VMware in cloning:

$ rm -Rf /etc/udev/rules.d/70-persistent-net.rules
$ init 6


7. After reboot, you should see the network interface has been changed to eth0 as screen shot below:



Done! Even though it required more steps to clone, it still can save a lot of your time doing OS installation especially if you just want to use the VM temporarily.


CentOS 6: Install Remote Logging Server (rsyslog)

In my office network, we have a lot of small devices like router and switches in our environment. My boss wants me to have a report on all of our network device for auditing purposes. To accomplish this objective, I need to have a server which run as logging server, accepting various type of logging from several devices. This method will ease up my auditing trail in one centralized location.

I will use my development server which run on CentOS to receive logs from my Mikrotik router, as picture below:


I am using following variables:

Rsyslog OS: CentOS 6.0 64bit
Rsyslog Server IP:
Router hostname: router.mynetwork.org
Router IP:

Rsyslog Server

1. Install Rsyslog package:

$ yum install rsyslog -y

2. Make sure you have following line uncommented in /etc/rsyslog.conf:

$ModLoad imuxsock.so
$ModLoad imklog.so
$ModLoad imudp.so
$UDPServerRun 514
$ModLoad imtcp.so
$InputTCPServerRun 514
$ActionFileDefaultTemplate RSYSLOG_TraditionalFileFormat
*.info;mail.none;authpriv.none;cron.none /var/log/messages
authpriv.* /var/log/secure
mail.* -/var/log/maillog
cron.* /var/log/cron
*.emerg *
uucp,news.crit /var/log/spooler
local7.* /var/log/boot.log
$AllowedSender TCP,,
$AllowedSender TCP,

3. We need to add following rules into /etc/rsyslog.conf so logs received from the router will be output into a file called /var/log/router.log:

:fromhost-ip,isequal,""                      /var/log/router.log

There are a lot of options you can use to define your remote logging rules, which you can refer to this page: http://www.rsyslog.com/doc/property_replacer.html

4. Open firewall port 514 on TCP and UDP:

$ iptables -A INPUT -m tcp -p tcp --dport 514 -j ACCEPT
$ iptables -A INPUT -m udp -p udp --dport 514 -j ACCEPT

5. Restart Rsyslog daemon to apply the configuration:

$ service rsyslog restart

6. We also need to rotate this log file so it will need eating up the server’s disk space. Create a new text file called router under /etc/logrotate.d/ directory:

$ vim /etc/logrotate.d/router

And add following line:

    rotate 5
    /bin/kill -HUP `cat /var/run/syslogd.pid 2> /dev/null` 2> /dev/null || true

Router (Rsyslog Client)

1. Mikrotik router supports remote logging. I just need to login into the Winbox > System > Logging and configure Actions as screenshot below:


2. The next thing, is we need to create the rules on which logging level do we want to be sent to the rsyslog server. Go to Winbox > System > Logging and configure Rules as screenshot below:



Now, the router should send the log remotely to the rsyslog server and we can check the router logs by running following command:

$ tail -f /var/log/router.log
Jan 8 17:23:28 system,info log action changed by admin
Jan 8 17:26:09 system,info filter rule changed by admin
Jan 8 17:26:09 system,info filter rule changed by admin
Jan 8 17:26:23 system,info PPP AAA settings changed by admin
Jan 8 17:26:40 system,info L2TP Server settings changed by admin
Jan 8 17:26:49 system,info filter rule changed by admin
Jan 8 17:26:50 system,info filter rule changed by admin