NAME [Toc] [Back]
dp - dedicated ports file used by DDFA software and Telnet port
DESCRIPTION [Toc] [Back]
The dp file has two uses:
Datacommunications and Terminal Controller Device File Access
The dp file is used by the Datacommunications and Terminal
Controller Device File Access (DDFA) software to allow
terminal server ports to be programmatically accessed from
HP-UX applications in the same way as devices connected
directly to the HP-UX system. It contains a one-line entry
for each configured terminal server port.
The dp file contains the information the DDFA software needs
to set up and manage an outbound connection to a specified
terminal server port. The file is parsed by the Dedicated
Port Parser (dpp) which spawns an Outbound Connection Daemon
(ocd) for each outbound connection specified in the file.
Telnet Port Identification
The dp file is used by the HP-UX telnet daemon (telnetd) to
identify the calling port and board of a telnet connection
from an HP Datacommunications and Terminal Controller (DTC).
At connection time, the host negotiates the telnet
environment option and the DTC replies with the port and
board number of the connecting device. Telnetd maps the
port and board numbers to the well-known name for the
device, which has previously been configured in the dp file.
Datacommunications and Terminal Controller Device File Access [Toc] [Back]
For outbound connections, an entry should have the following format:
dtc_name board/port pseudonym config_file log_level
The exact details of each field are given below.
Telnet Port Identification [Toc] [Back]
To configure the dp file for using the Telnet port identification
feature, the default file /usr/examples/ddfa/dp should be copied to a
new file and the copy configured with the appropriate values for the
incoming connections. The recommended procedure is to create a
directory to hold the dp file and the modified port configuration
An entry for this purpose should have the following format:
dtc_name board/port pseudonym
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The exact details of each field are given below.
Configuration Information [Toc] [Back]
There are three ways to specify a terminal server port:
+ Explicitly specify its IP address.
+ Specify the node name or the IP address of the DTC then
specify the board and port.
+ Specify the node name or the IP address of the terminal server
and the TCP port service address of the port.
Comments in the dp file can be appended by starting them with a #
character. Everything after the # is ignored by the parser. Fields
in the dp file are separated by space characters.
See ddfa(7) for more information on how to configure the DDFA
The fields of an entry of the dp file are as follows:
dtc_name This field is the node name or the IP address of the
terminal server being accessed or the IP address of
the port on the terminal server. A node name must
be defined in a name database.
board/port This field contains the terminal server port address
with the parts separated by the / character. It is
not necessary to pad the values with leading zeros.
The port address is not checked by dpp, but is
checked by ocd. Valid values are 0 through 7 for
board, and 0 through 31 for port (these restrictions
do not apply if the TCP port service address is
If the dtc_name field explicitly defines the node
name or the IP address of the terminal server port,
the value in the board/port field must be xx/xx (use
X or x).
If the field is of the form xx/n where n is a
decimal number, n is assumed to be the TCP port
service address and it is used when the connection
pseudonym This field is the absolute path of the device file
known to the system and the end-user application.
The device file name portion of the path name is
limited to 14 characters.
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pc_file_path This field is the path to a port configuration file
which contains the configuration information for the
terminal server port. This field is mandatory for
outbound connections as dpp uses the presence of
this field as its flag to spawn a daemon for the
log_level This field is the logging level for the particular
ocd and it determines the severity of messages sent
to /var/adm/syslog. The logging levels (and how
they relate to system logging levels) are as
0 Log only LOG_CRIT messages.
1 Log only LOG_CRIT and LOG_ERR messages.
2 Log only LOG_CRIT, LOG_ERR, and LOG_WARNING
3 Log all messages.
It is optional and may only be specified for
outbound connections. If it is omitted, the logging
level is set to 1.
EXAMPLES [Toc] [Back]
The following examples illustrate file entry syntax.
A printer is connected to port 1 of board 3 of a DTC with the IP
address 188.8.131.52. The device attached to the port can be
accessed with the HP-UX spooler by using the device file
184.108.40.206 03/01 /dev/telnet/lp1_ocd /usr/examples/ddfa/pcf
A printer is connected to a terminal server port with IP address
220.127.116.11. The board/port field contains xx/xx. The device
attached to the port can be accessed with the HP-UX spooler by using
the device file /dev/telnet/lp2_ocd.
18.104.22.168 xx/xx /dev/telnet/lp2_ocd /usr/examples/ddfa/pcf
A printer is connected to a port accessed with TCP port service
address 5001 of a terminal server with the IP address 22.214.171.124.
The device attached to the port can be accessed with the HP-UX spooler
by using the device file /dev/telnet/lp3_ocd.
126.96.36.199 xx/5001 /dev/telnet/lp3_ocd /usr/examples/ddfa/pcf
A terminal is connected to port 1 of board 2 of a DTC with the IP
address 188.8.131.52 and wishes to use Telnet port identification.
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184.108.40.206 02/01 /dev/telnet/tm02
WARNINGS [Toc] [Back]
In order to ensure that commands (such as ps) display the correct
device file name (that is, the pseudonym), all pseudonyms should be
placed into the directory /dev/telnet. If pseudonyms are not
specified for placement in this directory, the correct display of
device file names with many commands is not guaranteed.
In addition, in order to ensure that commands (such as w, passwd,
finger, and wall) work correctly, each pseudonym must be unique in its
first 17 characters (including the directory prefix /dev/telnet/). If
pseudonyms are not unique in their first 17 characters, the correct
functioning of many commands is not guaranteed.
FILES [Toc] [Back]
SEE ALSO [Toc] [Back]
dpp(1M), ocd(1M), ocdebug(1M), syslog(3C), pcf(4), ddfa(7).
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