Cisco Router accepting command, but doesn't show in running configuration

Posted on 2009-02-11
Last Modified: 2012-06-27
I was taking a lab and came accross a weird scenarios that I don't have an answer for. The router would accept the "router rip" command, but I noticed that it wasn't showing in the running configuration and rip wasn't routing. So, the router would take the command, but it really wasn't. The router would take the "router ospf" , "router eigrp" or any other command and it would show up in the running configuration. Finally, I found a weird file in the flash that I believe had a .sfg extension and had a number in the file name, something like 512 or 576. I deleted that file and rebooted and I was then able to configure router rip and it actually worked.
Has anyone seen this before?
Question by:asurf
    LVL 1

    Expert Comment

    I have not seen that file how ever I have seen the problem.
    Different versions of the IOS support different features. You may want to double check the version of the IOS on that device

    SHOW VER from the # prompt

    I would assume that 99% of the IOS's that are out there should support RIP

    Author Comment

    The version was exectly the same as other routers so that wasn't it.
    LVL 5

    Expert Comment

    Haven't come across it but sounds like a bug, what version of code and on what model router did this happen?

    Author Comment

    This was a 3825 with advanced ip services 12.4
    LVL 23

    Expert Comment

    There are cases where it's normal;  the command fails, is invalid, the command is a "duplicate" (i.e. same item twice in a list), or is not different from the default (silent suppression).

    I would have to guess that in this case, you've encountered a bug in the software, though.   If you were in an actual lab session, you get hit with
    one of life's little surprises,  I suppose....

    And that a .sfg  file appearing is not insignificant.
    I haven't heard of anything like that before with such a base level command.

    Perhaps Cisco never found it yet b/c hardly any 12.4 users would be utilizing RIP if they could help it.

    I suspect only Cisco would know the true nature of the bug, and only really by analyzing your device logs,  before the reboot, or by getting/forcing a crashdump
    If you've already rebooted, there's probably little evidence left of whatever went wrong, other than your config.
    LVL 5

    Expert Comment

    Can't find any bugs with 12.4 ios on 3800's, doesn't mean one doesn't exist as I think there's differences between the internal and external bug toolkits.

    Be interested if you get more in depth info.
    LVL 23

    Accepted Solution

    The Bug toolkit only lists the known, confirmed bugs.

    Sometimes, in an unusual setup, you might encounter a bug that hasn't been reported before.

    The ideal thing to do in situations like this (in a test lab), since you've rebooted,  would be to take your conf,  take your session log...  try to backtrack to the beginning of your session (I.E. set the config back to what it was before your session), and repeat the commands from your old logged  terminal session

    If you can reproduce the same unusual behavior again,  then you have a better chance of figuring out what causes the device to do that.

    If you can't, then it would be very hard to figure out what the bug might have been

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