In this tutorial we will show you how to authenticate to a already configured ldap server

1. This file "/etc/ldap.conf" is the 1st file that has to be modified as this is the file that tells the system which ldap server to authenticate too.
   

   
   host yourdomain.com
   base dc=yourdomain,dc=com
   uri ldap://yourdomain.com/
   ldap_version 3
   rootbinddn cn=Manager,dc=yourdomain,dc=com
   scope sub
   timelimit 5
   bind_timelimit 5
   nss_reconnect_tries 2
   pam_login_attribute uid
   pam_member_attribute gid
   pam_password md5
   pam_password exop
   nss_base_passwd		ou=People,dc=yourdomain,dc=com
   nss_base_shadow		ou=People,dc=yourdomain,dc=com
     

2. Now we have to add the passwd in this file "/etc/ldap.secret" so that we can authenticate to the ldap server
   

   password

3. Now we have to modify this file "/etc/nsswitch.conf"
   

   
   passwd:         files ldap
   group:          files ldap
   hosts:          dns ldap
   services:   ldap [NOTFOUND=return] files
   networks:   ldap [NOTFOUND=return] files
   protocols:  ldap [NOTFOUND=return] files
   rpc:        ldap [NOTFOUND=return] files
   ethers:     ldap [NOTFOUND=return] files
   netmasks:   files
   bootparams: files
   publickey:  files
   automount:  files
   sendmailvars:   files
   netgroup:   ldap [NOTFOUND=return] files
     

4. Now it is time to modify the files in /etc/pam.d/ directory.
   First file to be modified is "/etc/pam.d/login"
   

   auth	sufficient	pam_ldap.so
   account	sufficient	pam_ldap.so
   password	sufficient	pam_ldap.so
   session	sufficient	pam_ldap.so

   
   auth            requisite       pam_securetty.so
   auth            requisite       pam_nologin.so
   auth            sufficient      pam_ldap.so
   auth            required        pam_unix.so use_first_pass
   auth            required        pam_tally.so onerr=succeed file=/var/log/faillog
   account         required        pam_access.so
   account         required        pam_time.so
   account         required        pam_unix.so
   account         sufficient      pam_ldap.so 
   password        sufficient      pam_ldap.so
   session         required        pam_mkhomedir.so skel=/etc/skel/ umask=0022
   session         required        pam_unix.so
   session         required        pam_env.so
   session         required        pam_motd.so
   session         required        pam_limits.so
   session         optional        pam_mail.so dir=/var/spool/mail standard
   session         sufficient      pam_ldap.so 
   session         optional        pam_lastlog.so
     

5. Now we modify "/etc/pam.d/shadow"
   

   auth	sufficient	pam_ldap.so
   account	sufficient	pam_ldap.so
   password	sufficient	pam_ldap.so
   session	sufficient	pam_ldap.so

   
   auth            sufficient      pam_rootok.so
   auth            required        pam_unix.so
   auth            sufficient      pam_ldap.so use_first_pass
   account         required        pam_unix.so
   account         sufficient      pam_ldap.so
   session         required        pam_unix.so
   session         sufficient      pam_ldap.so
   password        sufficient      pam_ldap.so
   password        required        pam_permit.so
     

6. Now we modify "/etc/pam.d/passwd"
   

   password

   sufficient

   pam_ldap.so

   
   password        sufficient      pam_ldap.so 
   password        required        pam_unix.so shadow nullok
     

7. Now we modify "/etc/pam.d/su"
   

   auth	sufficient	pam_ldap.so
   account	sufficient	pam_ldap.so
   session	sufficient	pam_ldap.so

   
   auth            sufficient      pam_ldap.so
   auth            sufficient      pam_rootok.so
   auth            required        pam_unix.so use_first_pass
   account         sufficient      pam_ldap.so
   account         required        pam_unix.so
   session         sufficient      pam_ldap.so
   session         required        pam_unix.so
     

8. Now we modify "/etc/pam.d/sudo"
   

   auth

   sufficient

   pam_ldap.so

   
   auth            sufficient      pam_ldap.so
   auth            required        pam_unix.so use_first_pass
   auth            required        pam_nologin.so
     

9. In this file "/etc/pam.d/sshd" you have to add 3 entries, one for auth, one for account, and one for session.

   auth	sufficient	pam_ldap.so
   account	sufficient	pam_ldap.so
   password	required	pam_ldap.so

   
   auth            required        pam_nologin.so
   auth            sufficient      pam_ldap.so 
   auth            required        pam_env.so
   auth            required        pam_unix.so use_first_pass
   account         sufficient      pam_ldap.so
   account         required        pam_unix.so
   account         required        pam_time.so
   password        required        pam_ldap.so 
   password        required        pam_unix.so
   session         required        pam_mkhomedir.so skel=/etc/skel/ umask=0022
   session         required        pam_unix_session.so
   session         sufficient      pam_ldap.so 
   session         required        pam_limits.so