TCP/IP Configuration and Management Manual

Configuring the NonStop TCP/IP Subsystem
TCP/IP Configuration and Management Manual—427132-004
3-37
Configuration Files for the Internet Environment
Center (NIC) has authority over the root and the first level domains (for example, MIL,
COM, GOV, EDU, NET, ORG). NonStop received permission from the NIC to add the
subdomain NonStop. The network administrator at HP, however, now takes
responsibility for all the subdomains that are created at NonStop.
Domain names are written with the most specific name first and the most general last,
for example:
eeb.SWEd.nonstop.com
In this example, com is the highest level domain while eeb is the lowest level domain.
Consequently, it is impossible to use the domain name syntax to distinguish host
names from domain names.
By analogy, in the telephone network, each telephone number is divided into an area
code, a prefix, and the telephone number. Because most telephone calls are local, the
calls are not routed outside the local area unless they are destined for another area
code. This means that the switches for routing calls outside the local area are not
burdened with the traffic of local calls.
In the same way, most Internet traffic is local and the name resolution can be handled
by the local Domain Name Server. Only when there are non-local names that require
resolution are non-local servers accessed. A by-product of this condition is that instead
of addressing a local destination as
eeb.SWEd.nonstop.com
you can address it as
eeb
Domain Name Servers also are required to know the address of the parent server, that
is, the address of the server in the parent domain. Also, all the information of one
server is to be replicated in another server on the same level with no single point of
failure. This arrangement provides a backup in the event that one server fails.
RESCONF Details
The Domain Name Resolver (DNR) uses the information in the RESCONF file to
access the Domain Name Server (DNS). The RESCONF file contains the name of the
domain in which the current host is running (domain NonStop.COM). The following
example lists three DNS IP addresses (nameserver 127.1, nameserver 50.0.0.23, and
nameserver 50.0.0.36):
domain NonStop.COM
nameserver 127.1
nameserver 50.0.0.23
nameserver 50.0.0.36
The first server address is the primary server. If that server is unavailable, the resolver
contacts the second server. If the second is unavailable, the resolver tries to contact
the third server. Notice that the first server address is 127.1; this is the address you
would use if the current NonStop host had a server available. The RESCONF file that