Problems setting reverse telnet using HWIC-16A

Unanswered Question
Nov 24th, 2009

Hi,
I have trouble setting up a cisco 2811 as a terminal server using HWIC16A card and an octal cable.

The problem is that for some lines it works, and for some it does not even though they are setup the same.
When I do show line this is the output:

Router3#show line
   Tty Line Typ     Tx/Rx    A Modem  Roty AccO AccI  Uses  Noise Overruns  Int
*     0    0 CTY              -    -      -    -    -     5      0    0/0      -
      1    1 AUX   9600/9600  -    -      -    -    -     0      0    0/0      -
  0/0/0    2 TTY   9600/9600  -    -      -    -    -     0      0    0/0      -
  0/0/1    3 TTY   9600/9600  -    -      -    -    -     0      0    0/0      -
  0/0/2    4 TTY   9600/9600  -    -      -    -    -     0      0    0/0      -
  0/0/3    5 TTY   9600/9600  -    -      -    -    -     0      0    0/0      -
  0/0/4    6 TTY   9600/9600  -    -      -    -    -     0      0    0/0      -
  0/0/5    7 TTY   9600/9600  -    -      -    -    -     0      0    0/0      -
  0/0/6    8 TTY   9600/9600  -    -      -    -    -     0      0    0/0      -
  0/0/7    9 TTY   9600/9600  -    -      -    -    -     0      0    0/0      -
* 0/0/8   10 TTY   9600/9600  -    -      -    -    -     1      3 84547/0      -
  0/0/9   11 TTY   9600/9600  -    -      -    -    -     0     12 297130/0      -
*0/0/10   12 TTY   9600/9600  -    -      -    -    -     1      0    0/0      -
*0/0/11   13 TTY   9600/9600  -    -      -    -    -     2      1    0/0      -
0/0/12   14 TTY   9600/9600  -    -      -    -    -     1      0    0/0      -
0/0/13   15 TTY   9600/9600  -    -      -    -    -     0      0    0/0      -
0/0/14   16 TTY   9600/9600  -    -      -    -    -     0      0    0/0      -
0/0/15   17 TTY   9600/9600  -    -      -    -    -     0      0    0/0      -
  0/1/0   18 TTY 115200/115200- DialIn    -    -    -     0      0    0/0      -
  0/1/1   19 TTY 115200/115200- DialIn    -    -    -     0      0    0/0      -
   Tty Line Typ     Tx/Rx    A Modem  Roty AccO AccI  Uses  Noise Overruns  Int

    514  514 VTY              -    -      -    -   23     0      0    0/0      -
    515  515 VTY              -    -      -    -   23     0      0    0/0      -
    516  516 VTY              -    -      -    -   23     0      0    0/0      -
    517  517 VTY              -    -      -    -   23     0      0    0/0      -
    518  518 VTY              -    -      -    -   23     0      0    0/0      -
    519  519 VTY              -    -      -    -   23     0      0    0/0      -
    520  520 VTY              -    -      -    -   23     0      0    0/0      -
    521  521 VTY              -    -      -    -   23     0      0    0/0      -
    522  522 VTY              -    -      -    -   23     0      0    0/0      -
    523  523 VTY              -    -      -    -   23     0      0    0/0      -
    524  524 VTY              -    -      -    -   23     0      0    0/0      -
    525  525 VTY              -    -      -    -   23     0      0    0/0      -
    526  526 VTY              -    -      -    -   23     0      0    0/0      -
    527  527 VTY              -    -      -    -   23     0      0    0/0      -
    528  528 VTY              -    -      -    -   23     0      0    0/0      -
    529  529 VTY              -    -      -    -   23     0      0    0/0      -

Line(s) not in async mode -or- with no hardware support:
20-513
Router3#

As you can see there are some overruns on line 10 and 11 and I'm not sure wthat that means and what is causing it.

I'm able to connect to line 10 but when I connect to line 11 I get the message:

Router3#telnet 10.10.10.109 2012

Trying 10.10.10.109, 2012 ...

% Connection refused by remote host

This is how reverse telnet has been configured:

ip host Router1 2010 10.10.10.109

ip host Router2 2011 10.10.10.109

ip host Switch 2012 10.10.10.109

ip host ASA1 2013 10.10.10.109

ip host ASA2 2014 10.10.10.109

ip host ACE1 2015 10.10.10.109

ip host ACE2 2016 10.10.10.109

ip host MARS 2017 10.10.10.109

line con 0

login local

line aux 0

session-timeout 20

transport input all

line 0/0/0 0/0/14

session-timeout 20

transport input all

escape-character BREAK

telnet break-on-ip

telnet ip-on-break

line 0/0/15

line 0/1/0 0/1/1

password Password

login

modem Dialin

transport input all

stopbits 1

speed 115200

flowcontrol hardware

line vty 0 4

access-class 23 in

privilege level 15

login local

transport input telnet

Does anyone have an idea what is wrong?

Thank you.

I have this problem too.
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Peter Paluch Tue, 11/24/2009 - 06:46

Hello,

A couple of suggestions:

  1. Make sure that all your ports on the HWIC-16A card use the proper flow control, and also make sure that the devices connected to the octal cable are using the same method of flow control as well.
  2. On the configuration of the HWIC lines, use the no exec command. The reason is that if any message is sent from the attached devices to the HWIC card (such as logging message) while there is no session running on that port, the router with the HWIC card will start an EXEC session for that port, thereby disabling the option to reverse telnet to that port.

Best regards,

Peter

kasper123 Thu, 11/26/2009 - 03:06

Hi Peter,

Thank you for taking the time to reply.

I have added the no-exec command on all the lines.

Regarding your first suggestion (the flow control): I don't have anything set on the lines.

I see that the options for flowcontrol are:

Router3(config-line)#flowcontrol ?
  NONE      Set no flow control
  hardware  Set hardware flow control
  software  Set software flow control

What do you suggest I set for flow controll on the lines?

Peter Paluch Thu, 11/26/2009 - 11:41

Hello,

You are welcome. Regarding the flow control - while I am not completely sure I believe that the default is no flow control. I believe that for your needs, the software flow control is sufficient. So if possible, set the flow control both on your HWIC-16A and the devices connected to your terminal server to use the software flow control.

Best regards,

Peter

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