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Cisco 1720 router

Posted on 2011-03-01
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Last Modified: 2012-05-11
i got a second hand Cisco 1720 router, but it was set up the login and configuration already. and i don't know the login password/username. I want to reset to factory mode or sth original mode that i can start from the beginning. how?

also want to configure it to connect with my home ADSL modem for setting up a LAN lab, i want to setup it up similar to as a company that has a modem, router, then switch?

also, my current home internet is with a ISP that only gave me a username and password. not sure i got a static IP address or not, if so , am I still able to do what I want stated above?

thanks
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Question by:tonitoni99
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Expert Comment

by:GuruChiu
ID: 35013439
You can look at the password recovery procedure here:
http://www.cisco.com/en/US/products/hw/routers/ps221/products_password_recovery09186a0080094773.shtml

Almost all company I work with do not need a modem. I am not sure what you are asking for #2. You want an example configuration?

I use a Cisco router at my home as well. I have dynamic IP and I can do a lot of things I want. Not sure exactly what you want to do.
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WalkaboutTigger earned 500 total points
ID: 35013493
Many of the aDSL implementations do require a modem, at least in the San Francisco and Maui areas.

In addition to the password recovery procedure mentioned above by GuruChiu, I would advise the following:

Prior to writing one line of configuration, plan your network.  You can either contact your ISP to get a static IP address or you can configure the 1720 to authenticate for PPPoE and get a DHCP-assigned IP address from your ISP.  I would recommend going with the DHCP-assigned address as this will A) give you a better understanding of IOS functionality and B) reduce the cost as most aDSL providers charge a monthly fee for a static IP Address.

For an example configuration, please look at
http://www.cisco.com/en/US/tech/tk175/tk15/technologies_configuration_example09186a0080093fbf.shtml

For additional sample configurations for a Cisco 1700-series router, please look at
http://www.cisco.com/en/US/products/hw/routers/ps221/prod_configuration_examples_list.html
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Author Comment

by:tonitoni99
ID: 35013833
thanks very much GuruChiu and WalkaboutTigger, I am following the step provided by GuruChiu, I press the Ctrl+Break button and now in, when I run show running-config, it shows a list of 5 usernames with secret password;

I don't understand after typing "hostname(config)#enable secret cisco", what result will be?  Does it mean that 5 usernames' password all change to cisco, or there is a username called cisco, password is also cisco? how does this work, and how to create another username for myself?

thanks
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by:WalkaboutTigger
ID: 35013931
it means that you can use the serial cable to connect to the router using a password of "cisco" to get to enable mode.
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Author Comment

by:tonitoni99
ID: 35013958
thanks WlakaboutTigger, one more question related to you suggestion, if I configure the 1720 to authenticate for PPPoE and get a DHCP-assigned IP address from ISP, do I still need a modem?
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by:GuruChiu
ID: 35014222
no you don't. Your ISP already provide one.
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Author Comment

by:tonitoni99
ID: 35014250
ok, now i am able to get in and set a console password. using
Router#config t
Router(config)#line console 0
Router(config-line)# login
Router(config-line)# password Toni
then press Ctrl+Z

then I exit, it really asks me for the passoword. But when I turn off the router and turn back on, it doesn't ask me for password and just in to Router>, did I miss sth here, should I write to sth that can remember the setting? thanks
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Expert Comment

by:WalkaboutTigger
ID: 35014268
You need to follow the instructions to set the boot register back to the original value -
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Expert Comment

by:WalkaboutTigger
ID: 35014272
You need to follow Steps 13 and on in the Password Recovery Procedure
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Expert Comment

by:Istvan Kalmar
ID: 35014772
you need to roolback the config register:

hostname(config)#config-register 0x2102
CTRL+Z
write
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