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New Member

cannot upgrade IOS via tftp

I am trying to upgrade a 2821 via tftp to an IOS image that is 34MB. My "old reliable" tftp cannot handle files larger than 16MB so I donwload and tried two other servers. I tried SolarWindows and a server by Whitehorn. In both cases the router begins to download the IOS but it seems to keep going after downloading the IOS's 34MB and it begins the download again. It seems to loop in this manner until the flash is full and then the xfer quits complaing of the full flash! Is this a problem on the router end or should I look for yet another large file capable tftp server?




Re: cannot upgrade IOS via tftp

Try another TFTP program. Some may have problems sending files as large as 34MB.


Re: cannot upgrade IOS via tftp

You might be running into the issue described in this field notice:

The field notice also has some solutions you can try out.

New Member

Re: cannot upgrade IOS via tftp

I use 3comdaemon, I think it will work

New Member

Re: cannot upgrade IOS via tftp

TFTP has a limit of 32mb. I ran into this same issue while upgrading an ISR to support CME 4.0. You need to FTP the image. You can use a product called Bulletproof FTP server. Works like a champ.

New Member

Re: cannot upgrade IOS via tftp

I ran in to this exact problem 2 weeks ago. I ended up having our security folks open up FTP to the router from the server where the IOS was stored.

The FTP didn't take very long at all.

Cisco Employee

Re: cannot upgrade IOS via tftp

TFTPd32 works fine even with large files

Hall of Fame Super Silver

Re: cannot upgrade IOS via tftp

TFTPd32 is a good solution where you want to continue to use TFTP to transfer images.

There may be another aspect to consider in deciding which protocol you want to use to transfer images. FTP transfers will complete more quickly than a TFTP transfer of the same image. This is because TFTP transmits small packets and because TFTP transmits a packet and then waits for an acknowledgement before transmitting the next packet. However FTP transmits large packets and FTP uses the TCP sliding window to transmit several packets before it must stop and wait for an acknowledgement.

So from an efficiency standpoint there are some advantages in using FTP to transfre images. And the difference gets greater as the size of the image increases.



New Member

Re: cannot upgrade IOS via tftp

This is what I've been doing for the larger images:

ftp-server enable

ftp-server topdir flash:

This way, you can just use an FTP client to push the files to the flash, rather than getting a full-fledged FTP server. Connect with username "anonymous" and no password.

Don't forget to negate the commands when you're done, you don't want to leave an open FTP server. For a more secure solution or one that you want to leave up longer, you should be able to set up FTP usernames and passwords.


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