what is Open Ldap and how to configure it?

Open LDAP:

LDAP stands for Lightweight Directory Access Protocol. As the name suggests, it is a lightweight client-server protocol for accessing directory services, specifically X.500-based directory services. LDAP runs over TCP/IP or other connection oriented transfer services. LDAP is defined in RFC2251 "The Lightweight Directory Access Protocol (v3).

In simple Words "LDAP is a protocol for managing related information from a centralized location through the use of a file and directory hierarchy. It functions in a similar way to a relational database in certain ways, and can be used to organize and store any kind of information. LDAP is commonly used for centralized authentication."

How Does Open LDAP Work:

An LDAP client connects to an LDAP server and asks it a question. The server responds with the answer, or with a pointer to where the client can get more information (typically, another LDAP server). No matter what LDAP server a client connects to, it sees the same view of the directory; a name presented to one LDAP server references the same entry it would at another LDAP server. This is an important feature of a global directory service, like LDAP.

OpenLDAP Installation and Configuration:

I'm using the following Network Details:

System name: ldap.example.com
System IP: 192.168.0.254
Domain Name: example.com

Use the following steps:

1. Add user accounts for testing the ldap server :

                               #useradd ldapuser1

             #passwd ldapuser1

             #useradd ldapuser2

                      #passwd ldapuser2

2. Install packages of ldap: 

                             #yum install openldap* -y 

following packages installed by this command:

    compat-openldap.i386 0:2.1.30-6.4E

    openldap-clients.i386 0:2.2.13-6.4E

    openldap-devel.i386 0:2.2.13-6.4E

    openldap-servers.i386 0:2.2.13-6.4E

    openldap-servers-sql.i386 0:2.2.13-6.4E

3. Create ldap root user password after installing the open ldap packages: 

                             #slappasswd

                              New password:

              Re-enter new password:

              {SSHA}cWB1VzxDXZLf6F4pwvyNvApBQ8G/DltW

4. Update /etc/openldap/slapd.conf for the root password:

                             #vim /etc/openldap/slapd.conf

              database bdb 

              suffix "dc=example,dc=com" 

              rootdn "cn=Manager,dc=example,dc=com" 

              rootpw {SSHA}cWB1VzxDXZLf6F4pwvyNvApBQ8G/DltW
save & exit.

5. Migrate local users to LDAP:

                 # grep root /etc/passwd > /etc/openldap/passwd.root

                 # grep test1 /etc/passwd > /etc/openldap/passwd.test1

                # grep test2 /etc/passwd > /etc/openldap/passwd.test2

 Note: Repeat the same for the rest of users

6. Update default settings on file /usr/share/openldap/migration/migrate_common.ph : 

                       DEFAULT_MAIL_DOMAIN = “example.com”;

                       DEFAULT_BASE = “dc=example,dc=com”;

7. Start ldap service:
              #service ldap restart
              #chkconfig ldap on

8. Create ldif file for domain (example.com). using .ldif extension with file (for example: test.ldif):
              #vim /etc/openldap/test.ldif

                    dn: dc=example,dc=com
                 dc: example
                 objectClass: top
                 objectClass: domain
                 dn: ou=users,dc=example,dc=com
                 ou: users
                 objectClass: top
                 objectClass: organizationalUnit
                 dn: ou=Group,dc=example,dc=com
                 ou: Group
                 objectClass: top
                 objectClass: organizationalUnit

 
 save & exit.

9. Create ldif file for all test users:

#cd /usr/share/openldap/migration/
#grep root /etc/passwd > /etc/openldap/passwd.root
#grep ldapuser1 /etc/passwd > /etc/openldap/passwd.ldapuser1
#grep ldapuser2 /etc/passwd > /etc/openldap/passwd.ldapuser2
#./migrate_passwd.pl /etc/openldap/passwd.root /etc/openldap/root.ldif
#./migrate_passwd.pl /etc/openldap/passwd.ldapuser1 /etc/openldap/ldapuser1.ldif
#./migrate_passwd.pl /etc/openldap/passwd.ldapuser1 /etc/openldap/ldapuser2.ldif

                              

10. Modify all users ldif file like this:
                                      # vim /etc/openldap/ldapuser1.ldif

                   dn: uid=ldapuser1,dc=example,dc=com
                   uid: ldapuser1
                   cn: ldapuser1
                   objectClass: account
                   objectClass: posixAccount
                   objectClass: top
                   objectClass: shadowAccount
                   objectClass: radiusprofile  
                   description: 802.1x user
                   radiusFilterId: "Enterasys:version=1:policy=Enterprise User"
                   userPassword: {crypt}$1$rN6WLraT$9skdu7BpRUM6v7DiEhQXt1
                   shadowLastChange: 15419
                   shadowMin: 0
                   shadowMax: 99999
                   shadowWarning: 7 
                   loginShell: /bin/bash
                   uidNumber: 612
                   gidNumber: 612
                   homeDirectory: /home/ldapuser1

11.  Import all users in to the LDAP:

 

Add the Domain ldif file

#ldapadd -x -D “cn=Manager,dc=example,dc=com” -W -f  /etc/openldap/test.ldif

    Enter LDAP Password:

    adding new entry “dc=example,dc=com”

    adding new entry “ou=People, dc=example,dc=com”

Add the users:

#ldapadd -x -D “cn=Manager,dc=example,dc=com” -W -f  /etc/openldap/root.ldif

    Enter LDAP Password:

    adding new entry “uid=root,ou=People,dc=example,dc=com”

    adding new entry “uid=operator,ou=People,dc=example,dc=com”

#ldapadd -x -D “cn=Manager,dc=example,dc=com” -W -f  /etc/openldap/ldapuser1.ldif

    Enter LDAP Password:

    adding new entry “uid=ldapuser1,ou=People,dc=example,dc=com”

#ldapadd -x -D “cn=Manager,dc=example,dc=com” -W -f  /etc/openldap/ldapuser2.ldif

    Enter LDAP Password:

    adding new entry “uid=ldapuser2,ou=People,dc=example,dc=com”

 

 Note: Repeat the same for the rest of users.

12. Reastart the ldap service:

                            #service ldap restart

                            #chkconfig ldap on 

13. Test Ldap Server: 

       #ldapsearch -x -b 'dc=example,dc=com' '(objectclass=*)'

 

Add Monitoring targets to nagios server

Add Monitoring Targets To Nagios Server:

These Steps will perform on CLIENT MACHINE.

For adding monitor targets to nagios server, To do that you have to to install following two packages in your monitoring targets:

                                  

                                   1. nrpe

                                   2. nagios-plugin

These packages will not found in yum repository, so let us add the EPEL Repository to install packages.

Use the following command for installation:

                                   

                                   #yum install nrpe nagios-plugins-all -y

Configure Monitoring Targets:

For configure Monitoring targets edit /etc/nagios/nrpe.cfg and do this:

                                  #vim /etc/nagios/nrpe.cfg

                                  allow_hosts=127.0.0.1 192.168.0.220  ( Nagios server IP, add in line no. 81)

save & exit.

Start the nrpe service:

                                 #service nrpe restart

              #chkconfig nrpe on

Now come on NAGIOS SERVER MACHINE:

For add the clients:

                           #vim /etc/nagios/nagios.cfg

                            uncomment Line No. 52

                            cfg_dir=/etc/nagios/server

save & exit.

Create a directory "server", under "/etc/nagios":

                           #mkdir /etc/nagios/server

Create config file to the client to be monitored.

                            #vim /etc/nagios/server/clients.cfg

                               define host{

                               use                  linux-server

                               host_name      client

                               alias                client

                               address            192.168.0.200 (client ip)

                               check_period   24x7

                               notification_interval      30

                               notification_period        24x7

                               }

save & exit.

Restart Nagios service:

                             #service nagios restart

             #chkconfig nagios on

Open Nagios admin console in browser with server ip.
              If server ip is 192.168.0.220 then open browser and go to:

             http://192.168.0.220/nagios

and enter the username and password as administrator.

Click on "hosts". you will see the newly added client will be visible there.

You can define more clients by creating a seprate file under the "/etc/nagios/server" directory for each client.

Introduction of networking

A network can be loosely defined as a collection of two or more computers that have some sort of communication path between them.
                         In simple word, when two or more pcs connected and share data to each other called Networking.

Many parts required for networking. these are following-:

• Computer
• Shared Printer
• Send and Receive data for network card
• Cables

Networking is the practice of linking computing devices together with hardware and software that supports data communications across these devices.


Networking is the practice of linking computing devices together with hardware and software that supports data communications across these devices.