To use a custom LDAPs certificate install it into your hubs operating system.

Note you can use the LDAPTLS_CACERT environment variable to use a custom certificate for testing with ldapsearch before it has been installed into the system.

code
[root@hub]:~# env LDAPTLS_CACERT=/tmp/MY-LDAP-CERT.cert.pem ldapsearch -xLLL -H ldaps://ldap.example.local:636 -b "ou=people,dc=example,dc=local"