Basic LDAP AD authentication troubleshooting in Redhat Linux server

#id ADuser
//check the id status
  
#rpm -qa | grep ldap
//check if ldap package has installed

#cat /etc/ldap.conf
//check the config files

#ldapsearch -xv -b "ou=netgroup,dc=domainname,dc=com" nisNetgroupTriple=*ADuser* cn
//check if user present in ldap

#tail -f /var/log/secure
//check previous log if any login attempt are happened via ADuser

#hostname
#nslookup Hostname
#getent passwd ADuser
//check if ADuser directory are present

#cat /etc/pam.d/system-auth
#cat /etc/pam.d/password-auth
//verify the pam.d config files
  
#nslookup LDAPserver
#telnet LDAPserver:389
//check the connectivity between target machine to LDAP server
  
#/etc/init.d/nscd status
//check nscd status

#tail -f /var/log/messages
//check the main log