Developer Forum

I have a 1720 router (frane relay) remotely. I want to upgrade the IOS
using tftp, but I am wondering if it is a bad idea to do this via telnet to
a remote router that I dont have physical access to?

In article <Hj74g.17153$ XXXX@XXXXX.COM >,


Provided you have enough flash, you can copy the new image into the
router without disturbing anything.

For the experiments after that, "reload in 5 minutes" will *help*,
but you'll want to find a way to boot an image other than the default
image. [I'm relatively sure there is a way, but I haven't used IOS for
a few years and am getting rusty on such details.]

Walter Roberson schrieb:

...
conf term
boot system flash flash:c1720-your_NEW_imagename-12.4(13)T77.bin
boot system flash flash:c1720-your_OLD_imagename-12.4(13)T77.bin
exit

write mem

this way the router will attempt to boot the new image first.
if it doesn't find it in flash, or if it finds that its corrupted,
it will boot the old image.

regards ... rainer

In article <e2r1nq$25n$ XXXX@XXXXX.COM >,






I'm thinking of the case where the newly booted test image renders
the device up but unreachable (for whatever reason... e.g. different
defaults). If one has written the new image into memory as the first
image to try, then reboot would not fix the problem.

On the other hand, I cannot at the moment think of how to boot and
inject a "reboot in N minutes" after the boot -- if one arms the
reboot timer before booting to the test image, that boot action would
cancel the reboot timer.

Can one put a "reboot in 10 minutes" into one's startup config perhaps?
It isn't a configuration command, though...