Hi, Jeff.
On Thu, 27 Feb 1997 15:11:19 -0500, Jeff Kell <[log in to unmask]> wrote:
|I don't recall the details, and I've searched the archives off and on
|all morning with no luck other than a message I had sent in Nov 1995:
|
|> Hmmm... someone not long ago (Guy Smith?) figured out a way with
|> DTC-Manager to telnet to a DTC port and loop a cable over to an
|> adjacent port as a quick and dirty way to get telnet access to the
|> system.
It turns out that I am one of the biggest information pack-rats in the known
universe and had both of these messages in my mail folder (along with a
bazillion others). I hope this contains the info or pointers you need.
Forwarded message:
On Thu, 21 Sep 1995 14:14:56 -0400, Jon Diercks <[log in to unmask]> wrote:
|Subject: back-to-back DTC ports
|
|After seeing a message on HPADM that got my mind working, and doing some
|digging, I saw that one can telnet to a specific serial port on a DTC,
|*without* having a TAC card, by using specific TCP ports numbers mapped to
|DTC serial ports. For instance, telnet mydtc.xxx.yyy 1047 will connect to
|port 3 on slot 0. From there, I would think I should be able to
|back-to-back into another DTC port and thereby connect to my hp3000 - the
|end result being a single-port telnet server to the 3k.
|
|I haven't quite been able to make it work though. Can anybody offer any
|tips on how the two DTC ports should be configured in OVDTCMGR for this to
|work? I assume the cable connecting the two ports should be cross-wired for
|null-modem equivalence, right? Some of my experiments have gotten very
|close but failed due to some sort of 'feedback loop' where prompts were
|bouncing back upon themselves.
|
|TIA.
|
| -----------------------------------------------------------------------
| 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
| o________________________________________________________ ___
| _\_, \=`==^==>
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
On Mon, 25 Sep 1995 09:17:33 -0400, Jon Diercks <[log in to unmask]> wrote:
|Subject: Re: back-to-back DTC ports
|
|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
| o________________________________________________________ ___
| _\_, \=`==^==>
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
--
Jeff Woods
[log in to unmask] at Unison Software
[log in to unmask] at home [PGP key available here via finger]
"Be virtuous and you will be eccentric." -- Mark Twain (1835-1910)
P.S. (re: my quote du jour) Hmmm... Does it work the other way around too?
|
