The best way to show that your client is talking to the LDAP server is with the ldaplist command. Using ldaplist with no arguments dumps all the containers on the server. This works as long as the containers exist, and do not have to be populated. See the ldaplist(1) man page for more information.
If the first step works, you can try ldaplist passwd username or ldaplist hosts hostname but if they contain lots of data you might want to pick a less populated service, or pipe them to head or more.