Java™ Application Development on Linux - Dator

21.3 What’s in a Name? An Introduction to JNDI485features to look up arbitrary data for domains. These features are not used oftenbecause standard DNS has no authentication and authorization controls.Information in DNS is, inherently, public information.21.3.2.2 FilesystemsThe UNIX filesystems, NTFS, FAT, and other filesystems provide name-todatamappings that are compatible with JNDI. When they are combined withnetworked filesystems, such as SMB, CIFS, NFS, and even rsync and FTP,files can be made available over the network through JNDI.21.3.2.3 LDAPLDAP is the “Lightweight Directory Access Protocol.” There is an old joke thata platypus is a swan put together by a committee. If that is so, then it oftenseems that LDAP is the platypus of name and directory services.To be fair, LDAP has the heavy burden that goes with any standards thatare produced by a large committee-driven process. It has to try to be all thingsto all people. LDAP is a query and transport protocol specification of theISO X.500 naming and directory service standard. 4 Like other ISO and ANSIstandards, the specification is robust to the point of uselessness. LDAP is designedto allow every possible name system in the Universe to be subsumed intoa single, uniquely addressable Directory Information Tree. Every entry inLDAP has a distinguished name, which is an unambiguous specification of thename from the root of the tree. So far, this is like the other naming systems.There is a root, there are nodes at each layer, and then, at the bottom, there isdata. What makes X.500 and LDAP different is that each node consists of notjust a name, but of a type/name pair. An example of an LDAP name might be:url=http://www.multitool.net/,cn=M. Schwarz,o=MAS Consulting,st=MN,c=us4. If you are dying to know, X.500 is a naming and directory services standard from the InternationalStandards Organization (ISO), an international technical standards body. X.500 hasa transport and query protocol specification of its own, but it uses the ISO OSI (Open SystemsInterconnection) network protocol standard. OSI is rarely used because TCP/IP took off firstand has been hacked and hacked again to keep it alive and well. At one time, it looked like IPaddress space limitations would push the world to OSI protocols, but hacks like CIDR, privatesubnets, and now the (less hackish) IPv6 make it look like TCP/IP will be here for quite awhile. In a sense, then, LDAP is X.500 over TCP/IP. Or, to put it another way, LDAP is aTCP/IP implementation of ISO X.500.