Posts Tagged ‘3750’

Cisco 3750 Password Recovery

Monday, June 1st, 2009

This password recovery method also applies to at least the:
Cisco 2950, Cisco 2960, Cico 3550, Cisco 3560 and Cisco 3750 series.
The only difference will be for how long you will hold the mode button,
from my experience just try to hold it longer if it doesn’t work.
(It should be around 15 seconds for the 3750.)

Connect the PC to the console port

  • 9600 bits
  • 8 data bits
  • ‘none’ parity
  • 1 stop bit

If the switch is powered on, power it off and press and hold the mode button while you power on the switch again. Hold it for about 15 seconds until the SYS led is solid green, then release it.

The switch should then give you this prompt


To initialize the flash file system, run the command

switch: flash_init

The switch will now print a bunch of messages about the flash memory, hopefully one of them will be ‘done initializing flash’.
The next command is load_helper to load any helper images required by boot.

You can now list the contents of your flash by running dir flash:
There should be a file named ‘config.text’, you can rename this file

switch: rename flash:config.text flash:oldconfig.backup

To further boot the switch run the boot command, this will start the boot you are used to. When the switch is booted up, you will realize that the configuration is gone.. But you are enabled on the switch now.

To recover the old configuration:

Switch#rename flash:oldconfig.backup flash:config.text

And now to replace the running configuration with the backup

Switch#copy flash:config.text running-config
Destination filename [running-config]?

Press enter, and you will have your old switch configuration back and you are enabled.
Just remember to change your password now! 😀

Working with SDM templates on Cisco 3750 or 3560

Friday, September 5th, 2008

Sometimes we want different functionality from our layer 3 switches, someone may want a lot of VLANS, someone wants the switch to be able to have lots of routes, and someone wants to do IPv6 routing.

Luckily, Cisco have thought about this. You are able to use different SDM templates to achieve different usage of the memory.

To change the SDM template on the 3750, just use the following command:
switch(config)# sdm prefer (default|routing|vlan)
Here is a link to the specs: Table

On the 3560 you can also choose from access and dual-ipv4-and-ipv6
Link to specs here: Table

What you want to choose depends on what you want to do, now you know there exists a choice!