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CCNA – Cisco 3750 IOS Update – Suprafortix


Check out the link above, for far more info.


It is up to the user to decide whether to use FTP or TFTP for the file transfer, between the switch and the computer. Because this demonstration only utilises P2P network, no extra security is needed so I decided to use TFTP for the ease of use and no extra configuration. First, it is required to connect the switch and the computer with an Ethernet cable and set static IP addresses for the switch and the PC.

Because an Ethernet port is utilised for the data transfer it’s imperative to check what ports belong to what VLANs in the VLAN database. If a particular port does not belong to VLAN 1, the file transfer will not work, as the port requires extra configuration e.g. trunk link configuration. With this particular switch all ports were assigned to VLAN 1.

switch# show vlan —shows all VLAN and port assignment information

In a different scenario the ports might be taken by VLANs. If that’s the case, perform VLAN database clearing by removing vlan.dat from flash: directory, where VLAN entries are stored.

switch# delete flash: —deletes a particular file/files in flash: directory.

Because 3750 switches only have 16MB of flash memory, delete the old IOS image to free up some space as you won’t be able to fit both of the images in. I deleted renamed conf.text just to reduce the clutter.

DO NOT REBOOT ONCE YOU DELETED THE OLD IMAGE!!! You will have to access the switch via Hyper Terminal to upload and execute the binary, and it takes forever!!!

Next step is to assign static IP addresses for both PC and the switch to place them on the same network and connect the PC and the switch via an Ethernet cable.

After a while the switch recognises the connection, outputs acknowledgement messages and changes the light to green.

switch# conf t
switch (config)# int vlan 1
switch (config-if)# ip address

Same for the PC.

IP: MASK: for the switch.
IP: MASK: for the PC.

Make sure you can ping the switch, otherwise the transfer will fail.

Open up 3CDaemon and check where the TFTP directory is located, by default it’s C:\TFTP\. Drag and drop the new image in C:\TFTP\.

switch# copy tftp flash: —opens up a TFTP client with flash: as the desired directory to transfer files in. This command will require IP address of the TFTP server as well as source and destination filenames.

Address or name of remote host []?

Source filename []? c3750-ipbasek9-mz.122-55.SE1.bin

Destination filename [c3750-ipbasek9-mz.122-55.SE1.bin]? <ENTER>


3CDaemon shows that 12MB have been successfully transferred.

If the switch is rebooted at this point it will load the new image successfully, however the boot-up process will display a small error regarding the naming of the IOS image. The error occurs because the switch cannot find a binary image named as the default image name specified by the boot configuration file, if the switch doesn’t find the filename, it’ll boot from next available binary located in flash:. The error does not mean that the switch will not boot, it’s just cosmetic and I need it perfect without the error!

switch# conf t
switch (config)# boot system c3750-ipbasek9-mz.122-55.SE1.bin —changes the name of the default boot-up binary.

I have made a mistake here, I didn’t specify the flash: directory that the image resides in. This command says to look for the image in the root directory of the switch.

switch (config)# boot system flash:c3750-ipbasek9-mz.122-55.SE1.bin —the correct command.

You can also notice that the last screenshot still contains the boot error. I’ll repair the screenshots as soon as I get a change to play around with the switches again.

switch# reload

The switch realises that the boot configuration changed and prompts the user to confirm and save the changes.

New image booting up.

Check out the link above, for far more info.

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