1841 ADSL - does have VPN option!

Unanswered Question
Sep 28th, 2007

I need to get my 1841 ADSL router to be able to VPN to our Cisco Concentrator but the SDM says the image does not support this feature and I need to upgrade my IOS. I can't add any crypto's either too via the console.

The version info is:

router>sh ver

Cisco IOS Software, 1841 Software (C1841-BROADBAND-M), Version 12.4(1c), RELEASE SOFTWARE (fc1)

Technical Support: http://www.cisco.com/techsupport

Copyright (c) 1986-2005 by Cisco Systems, Inc.

Compiled Tue 25-Oct-05 17:10 by evmiller

ROM: System Bootstrap, Version 12.4(13r)T, RELEASE SOFTWARE (fc1)

router uptime is 2 hours, 29 minutes

System returned to ROM by power-on

System image file is "flash:c1841-broadband-mz.124-1c.bin"

Cisco 1841 (revision 6.0) with 114688K/16384K bytes of memory.

Processor board ID FCZ111020RF

2 FastEthernet interfaces

1 ATM interface

DRAM configuration is 64 bits wide with parity disabled.

191K bytes of NVRAM.

31488K bytes of ATA CompactFlash (Read/Write)

Configuration register is 0x2102

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Richard Burts Fri, 09/28/2007 - 08:22


It looks like your router now has the Broadband feature set. In my experience you need the Advanced Security feature set or the Advanced IP Services feature set to support IPSec VPN. I have confirmed by in looking at the software advisor on CCO that these are the only feature sets that support IPSec VPN. I notice that the code on that router is pretty old. While you are changing feature set I would suggest that you also go to a version that is mor recent.



whiteford Fri, 09/28/2007 - 08:45

Hi Rick,

I've downloaded c1841-advsecurityk9-mz.124-17.bin hope this will do it.

I have a tftp server on my laptop, how can I install this ios to replace the current one?


Richard Burts Fri, 09/28/2007 - 09:59


If you have down loaded the IOS is it on the hard drive of your laptop? Make sure that it is in the directory that your TFTP server will look in. Then establish connectivity between the router and your laptop. start the TFTP server software on your laptop. issue the copy tftp flash: on the router to iitiate the transfer.



whiteford Fri, 09/28/2007 - 10:14

Once I've done the transfer should I do anything else like reboot? Also will this automatically replace the old bin image on the router and use the new one?

Richard Burts Fri, 09/28/2007 - 12:28


Yes after you have transferred the image there are some things that you will need to do.

It may or may not replace the old image. The default is to keep the old image along with the new image. When you start the copy operation the IOS looks at how large the new image is and how much memory is available in flash. If there is enough room for both then the IOS will keep both images in flash. If there is not enough memory available then the copy will prompt you about deleting the old image.

So the old image might still be in flash or it might not. You should know which when the copy is completed. If there is only a single image (the new one) in flash then you will just need to reboot the router. (a copy run start before doing the reboot might be smart) If there are two images in flash then you will need to insert boot system commands into the config file of the router. In global config mode enter this command:

boot system flash:

exit config mode and copy run start to save the boot system command. Then reboot the router.



whiteford Fri, 09/28/2007 - 15:15

Thanks Rick. How do I get to the global config command is it conf t?

Once this is done I can the do the VPN I hope to our concentrator, do you think it will be similar to the 837 configs I use?

I could try using the SDM I suppose.

whiteford Mon, 10/01/2007 - 01:45


I'm getting a message "Not enough space on device"

I'm consoled to the device.

Richard Burts Mon, 10/01/2007 - 03:20


At first I thought that the message might indicate a problem with RAM or Flash to support your new image. So I checked the Feature Navigator on CCO and your new image requires 128 MB of RAM and 32 MB of Flash. The show version from your earlier posting shows that you have enough RAM and Flash for this image.

So now I am wondering in what context you are getting this message. Are you attempting to make config changes when you get it? Are you doing something else when you get it? And it would help to know whether you get this message over and over or just every once in a while? Perhaps you could post the exact syntax of the error message?



whiteford Mon, 10/01/2007 - 03:52


I managed to so a show flash and delete the current bin file which was 15mb, I then had enough space and uploaded the 20mb new IOS file and rebooted to find the new image is being used. So far so good, I just need to see if the VPN feature is working :)

Richard Burts Mon, 10/01/2007 - 04:05


That explanation makes a lot of sense. I somehow assumed that you had already loaded the code. The error of not enough space on device makes a lot of sense if you were attempting to do the image copy. And deleting files in flash that are no longer needed is the best way to deal with this.

That image does support VPN (I run that feature set on 1841s to do VPN quite often). I am not sure whether it is better to do the config changes using SDM or using command line. I personally prefer command line and that is partly because I am more familiar with it than I am with SDM. If you are more familiar with SDM it might make sense to start with SDM and then go to command line if there is something that SDM has difficulty with.




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