TCP/IP Configuration and Management Manual

Configuring the NonStop TCP/IP Subsystem
TCP/IP Configuration and Management Manual—427132-004
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Configuration Files for the Internet Environment
Remember, you must issue such an ADD DEFINE command to indicate that a HOSTS
file is to be used, as well as the name of the desired HOSTS file. Otherwise, the DNR
assumes it must use a DNS and consults a RESCONF file.
Also, note that you must set the TCPIP^HOST^FILE parameter at each terminal that
uses the TCP/IP network. Then, when you invoke a TCP/IP application with reference
to a host name, the DNR uses the appropriate HOSTS file. For convenience, include
such an ADD DEFINE command as an entry in the TACLCSTM file, so that the
command is executed automatically every time you log on to the NonStop system.
RESCONF File
The Domain Name Resolver (DNR) resolves domain names to IP addresses using
either a HOSTS file or a DNS to provide the translation. If you did not set the
TCP^HOST^FILE parameter, the DNR assumes it must use a DNS. To determine
which DNS to use, the DNR interrogates the RESCONF file. Thus, you must configure
the RESCONF file when using a DNS. Also, note that the NonStop TCP/IP sockets
library provides a procedure call to the DNR.
Domain Name System
The Domain Name System is a hierarchical naming system consisting of domains and
subdomains. The domain immediately above the current domain is called the parent.
The TCP/IP Domain Name System structure is illustrated in Figure 3-5.
It is important to remember that the Domain Name System is based on administrative
boundaries and not the topology of the network. The Internet Network Information
Figure 3-5. Domain Name System Hierarchy
011VST .VSD
ROOT
MIL COM GOV EDU NET ORG
nonstop purdue gm
SWEd
gab eeb jeb
buick cad