openLDAP server installation and configuration step by step – RHEL7

openLDAP directory service is based on a client-server model. LDAP transferred “Lightweight directory access protocol”   is a directory service protocol that runs on a layer above the TCP/IP stack. It provides a mechanism used to connect to, search, and modify Internet directories. The LDAP directory service is based on a client-server model. OpenLDAP Server installation

openLDAP is used to facilitate centralized user management. It eliminates users creation on each and every server, instead of creating users and there profile in all the servers we can create them in LDAP server and access from all the LDAP client machines.

Few advantages of openLDAP

• Global naming model ensures unique entries
• Allows for multiple independent directories
• Extensible to meet future/local requirements
• Runs directly over TCP/IP and SSL
• Has broad industry support
• Based on existing deployed technologies
• Schema definitions
• Schema publication
• Security features
• Extended operation framework
• Dynamic and pages search extensions

This tutorial will explain how to install and configure openLDAP server and it’s configuration with user home directory auto mount using NFS autofs

Please observe step by step and modify your requirements accordingly

Let’s start the configuration

Requirements – RHEL7/Centos 7 with minimal installation OR GUI installation is enough

Tested Centos7, RHEL7, RHEL7.1 and RHEL7.2 versions

Server Profile :-

• Packages : openldap, migrationtools
• Port Number: 389, 636

Step 1:  Installing LDAP packages using yum

[root@ark-ldapserver ~]# yum -y install *openldap* migrationtools 

generating LDAP admin password

[root@ark-ldapserver ~]# slappasswd New password:  Re-enter new password:  {SSHA}KczPx+72Gz5W4Tv58EgT8beoPsuxkekO

as shown in above slappasswd command will generate an password with encryption, please copy above encrypted password and keep it safe this password we are going to use in further configuration

add the generated password to below file and change olcSuffix olcRootDN olcRootPW  and add key file location as shown in below (bold ones have to modify)

[root@ark-ldapserver ~]# cd /etc/openldap/slapd.d/cn\=config/ [root@ark-ldapserver cn=config]# vi olcDatabase\=\{2\}hdb.ldif  # AUTO-GENERATED FILE - DO NOT EDIT!! Use ldapmodify. # CRC32 5514a54b dn: olcDatabase={2}hdb objectClass: olcDatabaseConfig objectClass: olcHdbConfig olcDatabase: {2}hdb olcDbDirectory: /var/lib/ldap olcSuffix: dc=arkit,dc=co.in olcRootDN: cn=Manager,dc=arkit,dc=co.in olcDbIndex: objectClass eq,pres olcDbIndex: ou,cn,mail,surname,givenname eq,pres,sub structuralObjectClass: olcHdbConfig entryUUID: 7ffd78be-8216-1035-9daa-e3230d8ea492 creatorsName: cn=config createTimestamp: 20160319120438Z entryCSN: 20160319120438.887404Z#000000#000#000000 modifiersName: cn=config modifyTimestamp: 20160319120438Z olcRootPW: {SSHA}KczPx+72Gz5W4Tv58EgT8beoPsuxkekO olcTLSCertificateFile: /etc/pki/tls/certs/arkitldap.pem olcTLSCertificateKeyFile: /etc/pki/tls/certs/arkitkey.pem

Now edit the file monitor.ldif and add modify dc=my-domain,dc=com to your domain as shown in below

[root@ark-ldapserver cn=config]# vi olcDatabase\=\{1\}monitor.ldif # AUTO-GENERATED FILE - DO NOT EDIT!! Use ldapmodify. # CRC32 3eb2863a dn: olcDatabase={1}monitor objectClass: olcDatabaseConfig olcDatabase: {1}monitor olcAccess: {0}to * by dn.base="gidNumber=0+uidNumber=0,cn=peercred,cn=external ,cn=auth" read by dn.base="cn=Manager,dc=arkit,dc=co.in" read by * none structuralObjectClass: olcDatabaseConfig entryUUID: 7ffd68a6-8216-1035-9da9-e3230d8ea492 creatorsName: cn=config createTimestamp: 20160319120438Z entryCSN: 20160319120438.886990Z#000000#000#000000 modifiersName: cn=config modifyTimestamp: 20160319120438Z

Test your LDAP configuration using below command, you may see few checksum errors no problem don’t bother

[root@ark-ldapserver cn=config]# slaptest -u 56ed4143 ldif_read_file: checksum error on "/etc/openldap/slapd.d/cn=config/olcDatabase={1}monitor.ldif" 56ed4143 ldif_read_file: checksum error on "/etc/openldap/slapd.d/cn=config/olcDatabase={2}hdb.ldif" config file testing succeeded

Step 2: Start LDAP server slapd.service

use below command to start and enable the service to start after the server reboot

[root@ark-ldapserver cn=config]# systemctl enable slapd.service ln -s '/usr/lib/systemd/system/slapd.service' '/etc/systemd/system/multi-user.target.wants/slapd.service' [root@ark-ldapserver cn=config]# systemctl start slapd.service [root@ark-ldapserver cn=config]# netstat -lt |grep ldap tcp 0 0 0.0.0.0:ldap 0.0.0.0:* LISTEN tcp6 0 0 [::]:ldap [::]:* LISTEN

Step 3: Generate certificate

generating x509 certificate for 365 days

[root@ark-ldapserver cn=config]# openssl req -new -x509 -nodes -out /etc/pki/tls/certs/arkitldap.pem -keyout /etc/pki/tls/certs/arkitkey.pem -days 365 Generating a 2048 bit RSA private key ..................+++ .................................................................................................................................+++ writing new private key to '/etc/pki/tls/certs/arkitkey.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]:IN State or Province Name (full name) []:Telangana Locality Name (eg, city) [Default City]:Hyderabad Organization Name (eg, company) [Default Company Ltd]:arkit Organizational Unit Name (eg, section) []:IT Common Name (eg, your name or your server's hostname) []:ark-ldapserver Email Address []: [root@ark-ldapserver cn=config]#

as mentioned above you can give the details are else just hit enter in all the fields. verify your certificate files by listing directory, key file names should match exactly with Step 1 configuration

[root@ark-ldapserver cn=config]# ll /etc/pki/tls/certs/ total 20 -rw-r--r--. 1 root root 1704 Mar 19 17:42 arkitkey.pem -rw-r--r--. 1 root root 1330 Mar 19 17:42 arkitldap.pem

Step 4: Change migration config

Go to directory path as mentioned below and edit the file migrate_common.ph file add few entries as shown in below screen

[root@ark-ldapserver cn=config]# cd /usr/share/migrationtools/ [root@ark-ldapserver migrationtools]# vi migrete_common.ph   $DEFAULT_MAIL_DOMAIN = "arkit.co.in"; $DEFAULT_BASE = "dc=arkit,dc=co.in"; $EXTENDED_SCHEMA = 1;

Step 5: Creating openLDAP database file

Now we just create an openLDAP database with file extension as .ldif

[root@ark-ldapserver migrationtools]# touch /root/base.ldif [root@ark-ldapserver migrationtools]# cat /root/base.ldif dn: dc=arkit,dc=co.in objectClass: top objectClass: dcObject objectclass: organization o: arkit co.in dc: arkit dn: cn=Manager,dc=arkit,dc=co.in objectClass: organizationalRole cn: Manager description: Directory Manager dn: ou=People,dc=arkit,dc=co.in objectClass: organizationalUnit ou: People dn: ou=Group,dc=arkit,dc=co.in objectClass: organizationalUnit ou: Group

Step 6: Creating users and groups

Create normal Linux users along with there primary groups

[root@ark-ldapserver migrationtools]# useradd ldapuser1 [root@ark-ldapserver migrationtools]# useradd ldapuser2 [root@ark-ldapserver migrationtools]# useradd ldapuser3 [root@ark-ldapserver migrationtools]# passwd ldapuser1 Changing password for user ldapuser1. New password: BAD PASSWORD: The password is shorter than 8 characters Retype new password: passwd: all authentication tokens updated successfully. [root@ark-ldapserver migrationtools]# passwd ldapuser2 Changing password for user ldapuser2. New password: BAD PASSWORD: The password is shorter than 8 characters Retype new password: passwd: all authentication tokens updated successfully. [root@ark-ldapserver migrationtools]# passwd ldapuser3 Changing password for user ldapuser3. New password: BAD PASSWORD: The password is shorter than 8 characters Retype new password: passwd: all authentication tokens updated successfully.

now gather all the users and groups information to separate files

[root@ark-ldapserver migrationtools]# cat /etc/passwd |grep ldapuser > /root/password [root@ark-ldapserver migrationtools]# cat /root/password ldapuser1:x:1001:1001::/home/ldapuser1:/bin/bash ldapuser2:x:1002:1002::/home/ldapuser2:/bin/bash ldapuser3:x:1003:1003::/home/ldapuser3:/bin/bash [root@ark-ldapserver migrationtools]# cat /etc/group |grep ldapuser > /root/groups

after that migrate your local users as openLDAP users

[root@ark-ldapserver migrationtools]# ./migrate_passwd.pl /root/password /root/users.ldif [root@ark-ldapserver migrationtools]# ./migrate_group.pl /root/groups /root/groups.ldif [root@ark-ldapserver migrationtools]# ldapadd -x -W -D "cn=Manager,dc=arkit,dc=co.in" -f /root/base.ldif Enter LDAP Password: adding new entry "dc=arkit,dc=co.in" adding new entry "cn=Manager,dc=arkit,dc=co.in" adding new entry "ou=People,dc=arkit,dc=co.in" adding new entry "ou=Group,dc=arkit,dc=co.in" [root@ark-ldapserver migrationtools]# ldapadd -x -W -D "cn=Manager,dc=arkit,dc=co.in" -f /root/users.ldif  Enter LDAP Password: adding new entry "uid=ldapuser1,ou=People,dc=arkit,dc=co.in" adding new entry "uid=ldapuser2,ou=People,dc=arkit,dc=co.in" adding new entry "uid=ldapuser3,ou=People,dc=arkit,dc=co.in" [root@ark-ldapserver migrationtools]# ldapadd -x -W -D "cn=Manager,dc=arkit,dc=co.in" -f /root/groups.ldif  Enter LDAP Password: adding new entry "cn=ldapuser1,ou=Group,dc=arkit,dc=co.in" adding new entry "cn=ldapuser2,ou=Group,dc=arkit,dc=co.in" adding new entry "cn=ldapuser3,ou=Group,dc=arkit,dc=co.in"

Verify the users using below command

[root@ark-ldapserver migrationtools]# ldapsearch -x cn=ldapuser3 -b dc=arkit,dc=co.in

Step 7: Allow firewall ports

we have to allow ldap and ldaps port numbers

[root@ark-ldapserver migrationtools]# firewall-cmd --permanent --add-service=ldap success [root@ark-ldapserver migrationtools]# firewall-cmd --permanent --add-service=ldaps success [root@ark-ldapserver migrationtools]# firewall-cmd --reload  success

That’s about openLDAP server configuration now we will see how to export LDAP users home directories

Step 8: Install NFS util packages

[root@ark-ldapserver migrationtools]# yum -y install rpcbind nfs-utils

Enable and start the NFS service

[root@ark-ldapserver migrationtools]# systemctl enable nfs-server.service  ln -s '/usr/lib/systemd/system/nfs-server.service' '/etc/systemd/system/multi-user.target.wants/nfs-server.service' [root@ark-ldapserver migrationtools]# systemctl start nfs-server.service [root@ark-ldapserver migrationtools]# systemctl enable rpcbind [root@ark-ldapserver migrationtools]# systemctl start rpcbind

configure NFS export

[root@ark-ldapserver migrationtools]# vi /etc/exports /home *(rw,sync) [root@ark-ldapserver migrationtools]# systemctl restart nfs-server.service 

Enable NFS and it’s supported Firewall ports

[root@ark-ldapserver migrationtools]# firewall-cmd --permanent --add-service=nfs success [root@ark-ldapserver migrationtools]# firewall-cmd --permanent --add-service=rpc-bind success [root@ark-ldapserver migrationtools]# firewall-cmd --permanent --add-service=mountd success [root@ark-ldapserver migrationtools]# firewall-cmd --reload success [root@ark-ldapserver migrationtools]# showmount -e localhost Export list for localhost: /home *.arkit.co.in [root@ark-ldapserver ~]# chmod 777 /home [root@ark-ldapserver ~]# systemctl restart slapd.service [root@ark-ldapserver ~]# systemctl status slapd.service

That’s it about openLDAP server configuration OpenLDAP Server installation OpenLDAP Server installation OpenLDAP Server installation OpenLDAP Server installation OpenLDAP Server installation OpenLDAP Server installation OpenLDAP Server installation

See Client side configuration

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