Help Please, Switching noob went to an auction. Cant log into a used switch.

[ThatSwitchNoob]

Hi,

Im a network administration student and wanted to do some hands on so i went to an auction and bought a used switch. Which i cant log into to do anything.

I get no activity off the comm port which is probably why it was at auction but maybe theres a management vlan set up and i could still get in?

The problem is i have little idea how to do so i have little experience with "putty" and dont know the commands very well but what i REALLY need help with is just getting to the CLI.
The switch is a cisco catalyst 3550 any help would be greatly appreciated.

 

[ThatSwitchNoob]

Update- i just remembered the whole you need a rollover cable or something to use a comm port. I guess my question is (since i dont have any cables like that) Is does anyone know a way to log in without knowing what its settings are through a regular ethernet port on the front.

 

[SirSub42]

If I recall from my cisco courses..the IP for the management is 10.0.0.1 and you can access that if you are plugged into any of the switch ports. If you want to access the CLI, then you will need the rollover/console connected to your computer's NIC. Then you can use putty or simply HyperTerminal to form a session. I believe all defaults except for the Flow Control, but I can't remember what we set it to. Anyhow, hope this helps. Keep me in mind if you need any help. I just finished the four course Cisco Network Discovery over the summer and would look forward to a refresher if you have any questions with getting your 3550 up.

 

[bill001g]

Lets assume someone did this correctly.

There will be no way to guess the management ip set on the switch or even which port is on the correct vlan and if it is very secure with 802.1x the ports will not even come on without central authentication.

Even if you were lucky enough to find a management ip and get the device to respond it will likely have any web interface disabled and have at least 2 passwords.

So step 1 is to buy a cisco console cable or seach the internet to build one yourself. These are special serial cables but a couple other vendors use the same ones.

But you are still screwed if they did it correctly. The switch will boot and you will be asked for a password which there is no way to guess.

So now you go to the cisco site and read the password recovery procedure for 3550 switches. It is much more complex than a cisco router so be careful to follow the directions.

Also be very sure to delete the vlan database since it not deleted by any of the common methods.

 

[sg4rb0]

Hi,

Im a network administration student and wanted to do some hands on so i went to an auction and bought a used switch. Which i cant log into to do anything.

I get no activity off the comm port which is probably why it was at auction but maybe theres a management vlan set up and i could still get in?

The problem is i have little idea how to do so i have little experience with "putty" and dont know the commands very well but what i REALLY need help with is just getting to the CLI.
The switch is a cisco catalyst 3550 any help would be greatly appreciated.

Lol I love the amount of noobs in this network forum its fun.

1.Unplug the power. Press and hold the mode button and plug/power it back on (STILL holding the mode button for around 15 secs)
2.On the command line, it will say. switch: Just type the following

switch: flash_init
switch: delete flash:config.text

3.reboot the switch = job done



For putty.
You need 2 cables:
- DB9 to serial cable (http://portuguese.alibaba.com/product-gs-img/rs232-db9-serial-to-rj45-cat5-ethernet-adapter-cable-de-294970427.html)
- serial to USB (http://media.cascade-uk.com/UniversalGadgets/Products/usb%20to%20rs232.JPG)

Connect the serial ends together then put the USB into your USB and the RJ45 into the console port. Install the driver on the PC. Then right click My Computer > Manage > Device Manager > Ports (COM & LPT) and check what COM# it is. The number will be in brackets. Note the COM number.

Open putty, click the serial radio button then change the COM port to the number you wrote down. Hit return a couple times = job done, your on the cli.