From: Calton, Doug (Doug.Calton@getronics.com)
Date: Tue Mar 02 2004 - 10:36:29 GMT-3
Very simple - think about what you will need to evaluate in your pattern. All even numbers have zero in the low order bit, and all odds have a one in the low order bit. So if you wanted to have no restriction in an octet EXCEPT even OR od, you would build a mask of all "don't cares" (1s) except for the last bit. E.g., I want even routes in the subnetwork 10.10.0.0, it would be
permit 10.10.0.0 0.0.254.255
If I wanted evens, it would be very similar, except for the third octet of the pattern being matched:
permit 10.10.1.0 0.0.254.255
If you want OTHER qualifications in the octet (like just a range of numbers that are all even or odd), you first build your basic filter and then set the last bit to zero in that octet.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Jans van Deventer
Sent: Tuesday, March 02, 2004 8:16 AM
To: ccielab@groupstudy.com
Subject: even / uneven access lists
Hi,
Could anyone give a quick overview of how to write an access-list for
even and uneven networks?
eg. allow networks 10.0.0.0, 10.0.0.2, 10.0.0.4 etc.
Regards,
Jano
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