From: Johnny Phan (johnny_d_phan@hotmail.com)
Date: Tue Apr 15 2008 - 12:41:56 ART
The correct answer is 192.0.0.0/3 ge 24 le 24 because:
1) You ONLY want to match the networks between 192-223.
2) You ONLY want to match the subnet mask of /24, no more, no less. Try it
out.
----- Original Message -----
From: "Scott Morris" <smorris@ipexpert.com>
To: "'Tarun'" <tarun.ccie@gmail.com>; "'Athaide, Dwayne'"
<DAthaide@eprod.com>
Cc: "'groupstudy'" <ccielab@groupstudy.com>
Sent: Monday, April 14, 2008 10:53 PM
Subject: RE: Another Prefix list question
> "ge 24" will permit subnetted Class C addresses as well, won't it? :)
>
> On the other hand, the "le 32" will also permit SUPERnetted addresses in
> that range. Just depends on what you are looking for.
>
> HTH,
>
>
> Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713,
> JNCIE-M
> #153, JNCIS-ER, CISSP, et al.
> CCSI/JNCI-M/JNCI-ER
> VP - Technical Training - IPexpert, Inc.
> IPexpert Sr. Technical Instructor
>
> smorris@ipexpert.com
>
>
>
> Telephone: +1.810.326.1444
> Fax: +1.810.454.0130
> http://www.ipexpert.com
>
>
>
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Tarun
> Sent: Tuesday, April 15, 2008 1:40 AM
> To: Athaide, Dwayne
> Cc: groupstudy
> Subject: Re: Another Prefix list question
>
> That prefix 192.0.0.0/3 ge 24 means the following.
>
> 1) It will match only the first 3 bits of the IP '192.0.0.0' which means
> any
> class C address because class C addresses are characterized by a '110' in
> the beginning of there 1st octet.
>
> 2) The 'ge 24' part means that the subnets mask of the class C address
> just
> matches has to be either equal to or greater than 24, i.e it will not
> match
> 192.168.2.3/16 for example.
>
> If you want to permit all "Class C networks" then the prefix list ideally
> should be
>
> ip prefix CLASS_C_NETWORKS permit/deny 192.0.0.0/3 le 32 - this would
> include all subnetted class C addresses as well.
>
> This is a good link on prefix lists:
> http://ccienotes.blogspot.com/2007/08/ip-prefix-list.html
>
> On 4/15/08, Athaide, Dwayne <DAthaide@eprod.com> wrote:
>
>> Please check
>>
>> If I want to permit only Class C networks
>>
>>
>>
>> Is this correct?
>>
>>
>>
>> 192.0.0.0/3 ge 24
>>
>>
>>
>> Thanks
>>
>>
>> Pass the CCIE in six weeks, Guaranteed!
>> http://www.certscience.com/CCIE
>> ______________________________________________________________________
>> _ Subscription information may be found at:
>> http://www.groupstudy.com/list/CCIELab.html
>
>
> Pass the CCIE in six weeks, Guaranteed!
> http://www.certscience.com/CCIE
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
>
> Pass the CCIE in six weeks, Guaranteed!
> http://www.certscience.com/CCIE
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
Pass the CCIE in six weeks, Guaranteed!
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