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using aux to manage other router by console

Unanswered Question
Jul 9th, 2006
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Dear ALL

There is 2 routers, one is connected with internet, and want to use a aux and rollover cable to connect the second router's console, so that can telnet to 1st router and console the 2nd router.

but what is the configuration of the 1st router? or need special config on 2nd router.

tks very much

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desai.jaideep Sun, 07/09/2006 - 23:42
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Aux. Port works only in following scenerio:


You cant connect directly from 1st aux to 2nd aux.It is only possible when


which is only possible in the case both the routers are configured.



samuel.lam Sun, 07/09/2006 - 23:45
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Tks for reply,

and is it possible like the configuration of access switch, like ip host 2001 and reverse telnet?

tks very much again

desai.jaideep Mon, 07/10/2006 - 03:24
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I believe reverse telnet is used to telnet a modem on access servers like 2509 etc.

I would like to know ur setup...

(1)Is router_A which is connected to internet is in the same LAN as router_b which is not connected to internet?

(2)Are'nt u able to first telnet the router_A and then telnet to router_B?

(3)There are serial-to-ethernet converters comming in market which are able to give virtual COM ports.These device once connected to IP, they can access any serial device remotely.

Check out such device at www.moxa.com

Pls rate all posts



theo_chimbga Mon, 07/10/2006 - 07:25
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Hi Samuel,

I have been trying to achieve the same. The following link provides useful alternative, which I am still testing. The only limitation is that access to the 2nd router is through AUX so IP must be configured on both ends. So this solution may not be suitable if you need to reset config on 2nd router remotely. http://www.cisco.com/en/US/tech/tk801/tk36/technologies_configuration_example09186a0080093c7b.shtml

tdrais Mon, 07/10/2006 - 13:20
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We do this all the time.

You just take a roll cable and plug it from the aux port of one router to the console port of the other router. You will telnet to the router that you used the aux port on. You need to do a show line and find the line number of the aux port. You then add 2000 to this and this is the port number you telnet to.

It varies router to router and sometimes depends on the modules installed.

So if you do a show line and it says the aux port is at 65 you telnet to x.x.x.x 2065

You will also need to add something like

Transport input all

under the configuration of the aux port.

samuel.lam Mon, 07/10/2006 - 18:24
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Tks for reply,

It seem that i can almost finish by using telnet to x.x.x.x 2065 ,

but once appear the username name, i can type the username, but after i type the password, it seems hang on the screen, .....

line aux 0

transport input all


tks very much

tdrais Tue, 07/11/2006 - 04:43
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It depends on the router that is asking for the username and password.

In some cases you will get asked twice. It sounds like the first router is doing authentication on the telnet command and it succeeds. It then allows you to connect to the console port of the other router. It appears that this other router is either not responding or you have a cable issue or something set on the console.

Make sure you are using a roll cable. These are the blue or black flat cables that used to come with routers.

Make sure you are using the default settings on the console. You can change the aux port to match the baud rate and other settings if you must but it is better to run with default.

Make sure you really should use 2065. Most 2600 routers use that but many other routers use 2001 and some change when you insert certain cards.


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