Now let's turn our attention to data describing hosts on a network. One of the most fundamental services provided in any TCP/IP network is the resolution of machine names to network addresses. The most widespread mechanism for looking up IP addresses is the Domain Name System (DNS). Again, coverage of DNS is beyond the scope of this book; for more information, see DNS and BIND, Fourth Edition, by Cricket Liu and Paul Albitz (O'Reilly).
Chapter 1 already made it clear that LDAP is not a replacement for a specialized directory service such as DNS. However, you can use LDAP effectively as a backend storage system for DNS zone files. Stig Venaas has written such a patch for Bind 9 using its new simplified database interface (SDB). The latest release of the patch for BIND 9.1 (or later) and the necessary schema file for OpenLDAP 2 can be obtained from http://www.venaas.no/ldap/bind-sdb/. For performance reasons, I recommend that you obtain the latest patch, rather than using the one included in the contrib/ subdirectory of the latest BIND 9 release.
Venaas has included a brief list of the steps necessary for integrating LDAP-sdb support in Bind 9. Here are the instructions contained in the INSTALL file of the ldap-sdb archive:
Copy the ldap.c source file to the bin/named/ subdirectory of the BIND 9 source tree.
Copy the ldap.h header file to the bin/named/include/ subdirectory of the BIND 9 source tree.
Edit bin/named/Makefile.in and add the following lines: