IOS TFTP BOOT

[Kamran Mustafayev]

Hello

Dears,

I want to solve one problem so here it is:

I need cisco router 2800 series boot ios image from network(tftp), when flash is corrupted or router doesnt see it, so it is impossible ?

if yes, please help with command, i used

boot system tftp:ios.bin but this does not help

thank you

[Richard Burts · Accepted solution]

I believe that you are on the right track using the boot system tftp command. But I believe that in the command you need to specify the address (and possibly the path to the image) for the tftp server.

HTH

Rick

[mishra.rahul]

Hi,,

If the flash is corrupted then how Router will boot and see the start-config to see any command in given through IOS,

If router will boot in condition of Corrupted flash then it will go ROMmon Mode,

and then you have to boot it in ROMmon mode from TFTP.

Here is the link which can help in ROMman mode case

Booting Cisco Router from TFTP in ROMmon Mode when Flash is corrupted

Regards

Rahul

[Marvin Rhoads]

Think about this - system is initializing, no IOS - rommon mode, no interfaces configured. How would the router know how to reach the tftp server during boot? You can load an image via tftp (link) on a running router but I'm not sure you can automatically boot via tftp on a router during initial load.

I believe you would have to manually intervene in rommon mode and specify some router parameters to give it an address, mask, gateway etc. so that it has enough information to reach the remote tftp server. See the rommon reference here for details.

[Leo Laohoo]

2800 right?  This one's got a Compact Flash (CF), right?  So why not use a multi-card reader and copy the IOS from your client to the CF using a multi-card reader?  It's faster.

[Richard Burts]

Leo

While I would agree that replacing the flash card might be an appealing option the original question was how to use boot from TFTP and I am trying to answer that question.

Marvin

Here is an extract from the command reference documenting the boot system tftp command. It does not say anything about it being limited to rommon. (and I believe that a long time ago I tested a normal boot using TFTP and it worked).

Router(config)# boot system tftp://192.168.7.24/cs3-rx.90-1 Router(config)# boot system tftp://192.168.7.19/cs3-rx.83-2

see this url for additional detail

http://www.cisco.com/en/US/docs/ios-xml/ios/fundamentals/command/A_through_B.html

HTH

Rick

[Marvin Rhoads]

Hi rick,

Yes I saw the command reference syntax when first replying.

I remain confused about the mechanics of it for a switch coming online after unexpected reload; as that what what I understood to be the context of the original post. Until the startup-config is loaded interfaces' addresses are not assigned and I don't see how the initializing device would know to reach anything outside itself without some sort of minimal bootstrap config.

I suppose if the tftp server is on the local LAN, one could posit some sort of PXE-boot analogue that would get a boot image and then proceed to load the startup-config but I haven't seen any documentation to lead me to believe such is the case.

[Leo Laohoo]

While I would agree that replacing the flash card might be an appealing option the original question was how to use boot from TFTP and I am trying to answer that question.

My apologies Rick.  Didn't intend to imply that your suggestion was incorrect or I disagree with you.  I was merely proposing a different option.

[Kamran Mustafayev]

Hello again

Thanks for answering

I used the nex scheme:

I set All ip adresses default gateway tftp parameters in rommon mode

after that i used tftpdnld -r command to download ios image into DRAM bypassing flash memory, so it decompressed image and everything worked fine, i used

boot system tftp ios.bin ip_address_of_tftp

But the point is router will not boot automaticaly if there is no FLASH before router powered on, i mean if we put out flash card before router turned on, router just goes into rommon mode, but if WHILE booting from FLASH there will be any error or interrupting and etc, router will boot ios from tftp, if connection will not enabled after 4 times router goes into rommon again

I dont know how too boot ios after total router rebooting, is it avaible ?

[Leo Laohoo]

Ok, let me try again ...

1.  Power down the router;

2.  Eject the CF;

3.  Use a multi-card reader and copy the IOS from your client to the CF;

4.  Re-insert the CF back to the router;

5.  Power on the router.