Follow the process below to get ldap working on Linux

First, Disable the firewall (or configure to allow LDAP traffic).

systemctl disable firewalld
systemctl stop firewalld

/etc/selinux/config
SELINUX=disabled

LDAP configuration

# DC1
echo -n | openssl s_client -connect ldap1.domain.com:1636 | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > /etc/openldap/cacerts/ldap1.pem
echo -n | openssl s_client -connect ldap2.domain.com:1636 | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > /etc/openldap/cacerts/ldap2.pem

# DC2
echo -n | openssl s_client -connect ldap3.domain.com:1636 | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > /etc/openldap/cacerts/ldap3.pem
echo -n | openssl s_client -connect ldap4.domain.com:1636 | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > /etc/openldap/cacerts/ldap4.pem

yum install sssd nss-pam-ldapd.x86_64 openldap-clients

scp solr:/etc/sssd/sssd.conf /etc/sssd/sssd.conf

service sssd start
systemctl enable sssd.service

authconfig --enableldap --enableldapauth --ldapserver=ldaps://ldap1.domain.com:1636/,ldaps://ldap2.domain.com:1636/ --ldapbasedn="o=devtech101.com,dc=subdomian,dc=com" --update

#modify /etc/pam.d/password-auth - change 1000 to 100
auth        requisite     pam_succeed_if.so uid >= 100 quiet_success

# Now Restart 
service sssd start

# Modify /etc/security/access.conf
+ : ALL : LOCAL
+ : root : ALL
+ : @sysadmin-group : ALL
+ : @webapp-group : ALL
-:ALL:ALL

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