dtelnetd

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# $Id: dtelnetd.txt,v 1.11 99/10/11 13:50:09 dan Exp $--------------------------------------dtelnetd - Deterministic telnet Server--------------------------------------

dtelnetd is a telnet server which allows you to explicitlyestablish a deterministic mapping between TCP ports andhost system pty slave nodes. This is useful in situationswhere applications are dependent on such fixed mappingsand when it is desirable to associate remote physicalterminal connections with specific pty devices.

--------------------------------------------Requirements and System Specific Information--------------------------------------------In order to use the dtelnetd server, your host system mustbe configured to emulate BSD-style ptys which adhere to theBSD naming convention (see step 2 under "Configuringdtelnetd" below).

1) Motorola System V/88 Release 4.0

This SVR4 based OS has a STREAMS-based pty subsystem

which can be configured to emulate BSD-style ptys(called BCS pseudo-terminals). This is accomplishedby adding the following line to the /stand/systemconfiguration file:

INCLUDE:BCSPTS

The system must then be rebooted for changes totake effect.

--------------------Configuring dtelnetd

--------------------Configuring the dtelnetd server is four-step process:

1) Add network service identifiers in /etc/services.

Each pty slave mapping requires its own seperateservice definition in the /etc/services file.These definitions have the following format:

/tcp

An example of three definitions, along with suggestedvalues is:

dtd-9000 9000/tcpdtd-9001 9001/tcpdtd-9002 9002/tcpetc...

The service names will be used in step 2 to specifythe port mapping.

NOTE: On Sun-based system using YP/NIS/NIS+, you will

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need to repopulate the NIS databases in order to makethe new service definitions take effect. This processis different depending on which resolution serviceyou are using. Refer to you Sun documention forinformation on how to propogate the service definitionsinto the appropriate system databases.

2) Add definitions to inetd.conf to establish port topty mapping. On most systems, this file is foundin /etc, however some systems (notably MotorolaSVR3.2 implementations) keep this file in /usr/etc.

Each of the above service identifiers requires acorresponding entry in the inetd.conf filein order to have inetd listen for connections onthose ports. These entries have one of thefollowing formats, depending on your systemtype (on one line):

MOTOROLA SYSTEM V/88 R4.0DIGITAL UNIX (Formerly DEC OSF/1)AIX 4.x

stream tcp nowait root/usr/sbin/dtelnetd dtelnetd -p

MOTOROLA SYSTEM V/88 R3.2 stream tcp nowait root

/usr/etc/inet/dtelnetd dtelnetd -p

NOVELL UnixWare 2.xSunOS 5.x (Solaris 2.x)

stream tcp nowait root/usr/sbin/in.dtelnetd in.dtelnetd -p

SCO SYSTEM V R3 stream tcp nowait NOLUID

/etc/dtelnetd dtelnetd -p

HP-UX Version 9 stream tcp nowait root

/etc/dtelnetd dtelnetd -p

The -p is necessary to provide the name of the slavedevice, but any other standard telnetd options maybe added as necessary.

corresponds to the service port definitionfrom step 1 (above). corresponds to the nameof the slave-side pty node which will be mapped to thisparticular port. This name must be a valid BSD-style

pty node of the following format:

/dev/tty[p-za-l][0-9a-f]

Any connections to the specified port will be made overthe specified slave pty. The name of this pty can thenbe obtained using ttyname() or other equivalent methodsonce the user is logged in. The following examples ofthe inetd.conf entries use the services defined in step1 (Motorola System V/88 R40):

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dtd-9000 stream tcp nowait root/usr/sbin/dtelnetd dtelnetd -p /dev/ttyp0



etc...

3) Place the dtelnetd server binary in the appropriatedirectory. This directory is the one specified inthe inetd.conf file above. Find the appropriatedirectory for your system and place the file there.

4) Activating the new services through inetd.

Before the changes made to the above files becomeeffective, inetd must be restarted. This is usuallyaccomplished by sending a SIGHUP to the inetdprocesses (which will then be automatically respawned).This can be done as follows:

kill -1

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