From: Elias Chari (elias.chari@gmail.com)
Date: Sun Jun 04 2006 - 15:08:28 ART
Faryar,
It is not meant to solve all your acl scenarios, but if you get 3 or 4
networks then it can get messy using binary. My brain works better in
decimal...-)
In any case I worked it out using only decimal numbers, as per my previous
post.
Regards,
Elias
On 6/4/06, Faryar Zabihi (fzabihi) <fzabihi@cisco.com> wrote:
>
> Way too complicated. Just think about the networks you need to include.
> See what octets you need to work on. Then just wildcard is the
> difference in that octet(from first network to last). Make sure you can
> actually use one statement to do this. Sometime you would need to
> blocks. Take the mcast range for example. How can you include all in
> one ACL?
> I have never run across too complicated of a scenario for this not to
> work, but you can definitely get an ugly one. Just make sure you think
> about it. Bit manipulation can be a biotch and time consuming as you
> pointed out.
> This probably doesn't make sense..but it has worked for me
> everytime...well I did fail the lab but I don't think it was ACLS
>
> Faryar
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> elias.chari@gmail.com
> Sent: Sunday, June 04, 2006 12:29 PM
> To: ccielab@groupstudy.com
> Subject: Most efficient ACL to match multiple networks - easier way?
>
> Hi Group,
>
> I guess you have all come across a requirement to match multiple
> networks with a one line ACL.
>
> I understand the theory i.e AND operation to get the network part and
> X-OR for the wildcard. Now writting out all the networks in binary and
> doing the operations is time consuming and quite easy to make a mistake
> when under pressure.
>
> I have tried to work it out using the AND and X-OR functions on the MS
> calculator and whilst it woks ok for the AND operation for multiple
> networks, it fails on the X-OR function as it does a comparison of two
> networks at at time.
>
> Has anybody worked out how to get the calculator to compare multiple
> numbers using the X-OR function?
>
> BTW it works for AND when using the networks in decimal format...-)
>
> If we crack this, it could potentially save us quite a bit of time.
>
> Regards,
> Elias
> PS - The equation for an X-OR gate (for those not familiar with it and
> may be interested) is:
> __
> Y = (A+B)(AB)
>
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