1. /etc/resolv.conf should contain the nameserver ( i.e. the DNS server address, where searching should go). This is present in both DNS clients and servers.
2. /etc/named.conf
this file is on the DNS server, and it contains names of files that contains host-to-name mappings database.
For example, when you query the hostname of an ip such as 192.168.1.2, you go the DNS server (the address of which is on resolv.conf file), then on that server the name of the file that contains the answer should be in named.conf
Now, don't forget another important file:
/etc/nsswich.conf
this file contains the searching priority, whether the system should consult DNS server, or NIS, or NIS+, or local file...and so forth.