At 03:35 PM 9/22/95 -0700, Michael Hensley wrote:
>Now, to pay "us" all back for the help, how about writing up the whole solution
>and submitting it for inclusion in the FAQ? You'll be famous!
Good idea Michael. Here's some notes. Hopefully the FAQ maintainer (Chris
Bartram?) will pick this up.
Using Back-to-Back DTC ports to permit inbound telnet without a TAC
===================================================================
With OpenView DTC Manager, a DTC port can be configured as one of three
types - terminal, printer, or host. If configured as a host port, the port
can be accessed via telnet to the DTC's IP address at a specific TCP port
number, as calculated by the following formula (taken from HPSL document
N2X94121300C
(http://support.mayfield.hp.com/kdb-bin/wwwsdoc.pl?DOCID=N2X94121300C)):
( ( ( 32 * dtc_board_number ) + dtc_port + 1 ) * 256 ) + 23
So, for example, for a dtc at IP address 199.8.123.123 to connect to port 2
on board 0 you would use "telnet 199.8.123.123 791".
Once this port is accessible via telnet, if it is cabled to another DTC port
which is configured as a normal terminal, then the incoming telnet can be
passed serially to a DTC> prompt, or if switching is not enabled, pass
directly to the default destination for that port. If the destination is an
MPE/iX system, then we have effectively translated from telnet to rs232 to
AFCP, providing a means for a user with telnet but not NS/VT capability to
access the MPE/iX system from the network, without a Telnet Access Card in
the DTC.
Miscellaneous supplemental notes:
The cable connecting the two DTC ports does *not* need to be crossed (i.e.
null-modem).
Recommend not using speed sensing on either port, but rather just set them
both to 19200bps.
The serial link between DTC ports is the slowest link in the chain here, so
even if the telnet user has a T1 line, they'll only get 19200bps throughput.
Only one telnet connection per port at a time. If a second user tries to
connect, they'll appear to get connected but will not receive any prompts.
Some obvious security concerns are raised by this configuration. NS/VT
provides a certain level of 'security by obscurity', while telnet access is
more widely understood and available.
Disconnecting from the telnet session is not automatic. Upon logging off
the session will be left at a new logon prompt. Most telnet clients use ^]
to escape back to a telnet> prompt, from which a 'quit' command usually
closes the connection.
-----------------------------------------------------------------------
Jon Diercks -------- mail: [log in to unmask]
Programmer/Analyst /|| | chat: powwow:[log in to unmask]
Computing Services /_|| | WWW : http://rowlf.csv.anderson.edu/
Anderson University / ||__| tel : (317)641-4305
Anderson, IN 46012 -------- fax : (317)641-3851
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