We do not support multiple (redundant) ldap servers with our NAS or NAS-XSR products. This why you are not able to enter another IP Address.
Single LDAP server information is below.
Workgroup(external LDAP):
In case of external LDAP (Lightweight Directory Access Protocol), the NAS server will use users/groups from external LDAP server. Please fill-in all fields accordingly. In advanced setting you can set Base DN, LDAP administrator DN (Distinguished Name) and LDAP administrator password. Base DN should looks like "dc=server,dc=nas"(DC - Domain Component), where "server" and "nas" can be set as they are set on remote LDAP server. In LDAP administrator DN you should set previously entered base DN with prefix like "cn=admin," (CN - Common Name). Users should be stored in Organization Unit (ou) "People", groups in "Groups", adn computers in "Computers".