Telserv Manual

Using TELNET to Connect to Telserv
Telserv Manual—427174-009
8-4
Host Names and Name-Resolution Files
Host Names and Name-Resolution Files
A host name is the official name by which the host system is known to the Internet. On
a NonStop S-series system, the host name can be associated with the system’s
Internet address in the name-resolution configuration file, or the name can be mapped
to an address through a name server. You can ask the system manager of the host
system what the host name is. You can also use an alias for a NonStop host if one is
defined in the name-resolution file.
Normally, host names are converted to Internet addresses by a Domain Name server.
If your network does not have one, host names are resolved through a name-resolution
file. For a name-resolution file, you can choose either a HOSTS-type file or an
IPNODE-type file. Your choice depends on the NonStop TCP/IP product that you are
using and, for NonStop TCP/IPv6, the mode (INET, INET6 or DUAL) in which you are
running.
HOSTS File
If you are establishing communication by means of IPv4 addresses exclusively, you
should use a HOSTS file. If you are running NonStop TCP/IPv6 in DUAL mode, you
can use a HOSTS file for resolving the IPv4 addresses.
The HOSTS file is a simple edit type file that contains an entry for each remote host
known to your system. Specify each remote host's IP address, host name, and alias.
Each entry in the HOSTS file has the following format:
IP_address host_name [alias...]
The IP address is a 32-bit numeric value expressed in dotted decimal form. The IP
addresses must begin in the first column of an entry in your edit file. The host_name
and aliases are alphanumeric and separated by at least one space.
You must configure the DNR to use a HOSTS file; otherwise, DNS is assumed. Use
the ADD DEFINE command of TACL to set the TCPIP^HOST^FILE environment
variable.
The TACL ADD DEFINE command that follows is an example:
2> ADD DEFINE =TCPIP^HOST^FILE, FILE $SYSTEM.ZTCPIP.HOSTS
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 DNS and consults the RESCONF file.
Note that you also 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 executes automatically every time you log onto the NonStop system.
For more information about the HOSTS file, see these manuals: