telnet to 3com switch, then

#system

#control

#softwareUpgrade

then enter the TFTP server IP.

telnet to the 3com switch, the go to

#system

#backup configuration

#save

# key in your TFTP server ip.

**make sure your 3com is able to ping the TFTP server.

Cisco – Catalyst 3500 series XL
———————————————
Recovering From Corrupted Software
1.connect through console port

2.switch:prompt

3.switch:copy xmodem: flash:image_filename.bin
  Then go to transfer and use xmodem to transfer the file.

4.switch:set boot flash:image_filename.bin

5.then reboot it.

Cisco – Catalyst 3500 series XL
——————————————————————-
Recovering from on Lost or Forgotten Password
1.connect terminal to the console port and set the line speed to 9600 baud. then reboot the router

2.Press in the “mode” button and release the button when a second or two after the LED above port 1X goes off

3.switch:flash_init

4.switch:load_helper

5.switch:dir flash:

6.switch:rename flash:config.text flash:config.text.old

7.switch:boot
  then it wil prompted to start the setup program, Enter N at the prompt
 Continue with the configuration dialog? [yes/no]:N

8.switch>enable

9.switch#rename flash:config.text.old flash:config.text

10.switch#copy flash:config.text system:running-config
   source filename [config.text]?
   Destination filename [running-config]?
 
  Press RETURN in response to the confirmation prompts.

11.switch#config terminal

12.switch(config)#enable secret <password>

13.switch(config)#exit

14.switch#copy running-config startup-config