There are three files in this directory.

dns.tar.Z      contains the .c files and perl scripts from DNS and
               BIND, Third Edition.

dns.2ed.tar.Z   contains the .c files and perl scripts from DNS and 
                BIND, Second Edition.  The files for Chapter 12 in 
                this edition correspond to the files for Chapter 11 of
                the first edition, and the files for Chapter 14 of 
                this edition   correspond to Chapter 13 of the first 
                edition.

dns.1ed.tar.Z   contains the .c files and perl scripts from the first
                edition of DNS and BIND.