tftp to remote server

djames · ‎01-04-2008

I've had an ongoing issue that I have been trying to figure out. I want to be able to upload a new IOS to a remote router from a tftp server running on my laptop. The cisco router is running at a remote branch. I have access to the router via a vpn tunnel. There are no acls on the router that would prevent me from preforming this action. As a test I was able to tftp the running config to a tftp server on the local subnet as the router, however, I want to be able to tftp to the router from my tftp server. Is there any issues concerning tftp to remote cisco routers?

akemp · ‎01-04-2008

No, tftp just has to be enabled on the device for it to work, by default its disabled as its insecure.

djames · ‎01-04-2008

What is the command to allow tftp on a Cisco router? I did not know there was one. When router and tftp server are on the same subnet there is no problem. Unfortunately I do not have a tftp server at each remote site(30+)

Danilo Dy · ‎01-05-2008

Hi,

Can you put an ACL in your router to see if the TFTP connection reach there? Because if you are trying to TFTP via internet or thru multiple WAN segments. Chances are, routers between your laptop and the router you are trying to access blocks TFTP port. This could be because of this http://www-search.cisco.com/en/US/products/sw/voicesw/ps556/products_security_notice09186a00801aedd6.html and similar issues in the past at the height of worms, virus, ddos attacks.

Regards,

Dandy

Richard Burts · ‎01-05-2008

David

I am not clear what Andy was referring to about TFTP needing to be enabled and my best guess is that he may be assuming that there is a firewall involved which might need to enable TFTP. Since you mention access is via VPN I doubt that the firewall is the issue.

Without some additional information, my first guess is that there is an access list which identifies traffic to be protected by the VPN and that one side or the other is not including the TFTP as traffic to be protected by VPN. Can you provide some details about how the VPN is configured and how "interesting" traffic is identified on both ends?

HTH

Rick

HTH

Rick