TCP/IP Configuration and Management Manual

Configuration Reference
TCP/IP Configuration and Management Manual—427132-004
A-9
Domain Name Server Files
Remote Server
To set up a host that uses a remote server instead of a local server to answer queries,
set up the file $SYSTEM.ZTCPIP.RESCONF as specified in RESCONF File on
page 3-36. This file designates which domain name servers on the network should be
sent queries. Do not create (set up) this file if you have a local server running, since if
this file exists, it is read almost every time gethostbyname or gethostbyaddr is called
programmatically.
Cache Initialization
The domain name server needs to know the servers that are the authoritative domain
name servers for the root domain of the network. To provide this information to the
domain name server, you must prime the domain name server's cache with the
addresses of these higher authorities. The location of the file containing the cache
entries is specified in the boot file. This cache file uses the Standard Resource Record
Format (also known as Masterfile Format).
Domain Data Files
Any of four standard files can specify the data for a domain: DNSCACHE, DNSLOCAL,
DNSHOSTS, DNSREV. These files use the Standard Resource Record Format.
DNSCACHE The name server needs to know the server that is the authoritative
name server for the network. You must prime the name server’s
cache with the address of higher authorities. Specify the location of
this initialization file in the boot file.
DNSLOCAL This file specifies the address for the local loopback interface, better
known as local host (or me). The network address is 127.0.0.1.
Specify the location of this file in the boot file.
DNSHOSTS This file contains all the data about the machines in this zone.
Specify the location of this file in the boot file.
DNSREV This file specifies the IN-ADDR.ARPA domain. This special domain
allows address-to-name mapping (reverse of name-to-address
mapping). Because Internet host addresses do not fall within domain
boundaries, this domain was formed to allow inverse mapping. The
IN-ADDR.ARPA domain has four labels preceding it, which
correspond to the four octets of an Internet address. You must
specify all four octets even if an octet’s value is zero. The Internet
address 128.33.0.14 is located in the domain 14.0.33.128.IN-
ADDR.ARPA. This reversal of the address is awkward to read, but
allows for the natural grouping of hosts in a network.