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573 Views 3 Replies Latest reply: Apr 13, 2012 5:23 PM by jneiberger RSS

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Classless routing

Apr 13, 2012 1:46 PM

matthew 205 posts since
Feb 25, 2011

I came across a question on Boson Netsim asking what happens to a packet sent to a subnet in the same classful network with no existing subnet and the correct answer said it sends the packet to the default route or discards it if the ip classless command is configured.  The question never stated wether classless routing was in use, which is the determining factor of wether the ip classless command is valid.

  • kelsonlawrence 169 posts since
    Apr 30, 2010
    Currently Being Moderated
    1. Apr 13, 2012 1:57 PM (in response to matthew)
    Re: Classless routing

    Hi Matthew,


    May I ask that you submit a support ticket for this question, please? If something is amiss, we'll fix it. If not, we'll explain why we did it that way.


    Kind regards,



    Boson Software

  • Martin 13,070 posts since
    Jan 16, 2009
    Currently Being Moderated
    2. Apr 13, 2012 2:17 PM (in response to matthew)
    Re: Classless routing

    ip classless is on by default nowdays;


    I think it should be "discards it if the no ip classless command is configured."

  • jneiberger 465 posts since
    Jun 10, 2010
    Currently Being Moderated
    3. Apr 13, 2012 5:23 PM (in response to matthew)
    Re: Classless routing

    Your question is a little confusing. If "classless routing is configured", then "ip classless" is configured. If that is the case, the default route would be taken. If "no ip classless" is configured, the packet would be discarded unless the default route was learned from OSPF or IS-IS, in which case "no ip classless" is ignored and classless routing rules apply.


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