Re: Class "A" prefix-list

Ugh... You're killing me "Hammer cisco". Now I'll have to adjust my email
rules. :)

 -Hammer-

"I was a normal American nerd."
-Jack Herer

On Wed, Jun 1, 2011 at 7:37 PM, Narbik Kocharians <narbikk_at_gmail.com> wrote:

> Hammer,
>
> Q1:
>
> I did that for illustration purpose ONLY. I was trying to show how you
> match
> class A networks that are NOT subnetted, and i was also trying to setup the
> grounds for the second item that i was showing.
> Q2:
>
> If the question does not state any details, i would recommend doing it for
> all class A major networks and subnetted class A networks.
> On Wed, Jun 1, 2011 at 2:56 PM, Hammer cisco <cisco.iers_at_gmail.com> wrote:
>
> > Hi Narbrik,
> >
> > thanks for your illustrations , but i have 2 comments :
> >
> > 1- i think 0.0.0.0/1 ge 8 is enough instead of saying "ge 8 le 32 "
> as
> > mentioned in your example below
> >
> > 2- if the the required in a certain routing protocol to deny all Class A
> > network address routes :
> > what do u recommend ?
> >
> >
> >
> > On 2 June 2011 00:21, Narbik Kocharians <narbikk_at_gmail.com> wrote:
> >
> >> *
> >>
> >> Class A networks that are NOT subnetted:
> >>
> >>
> >>
> >> R2(config)#ip prefix-list Class-A seq 5 permit 0.0.0.0/1 ge 8 le 8
> >>
> >>
> >>
> >> Class A networks are identified as follows:
> >>
> >>
> >>
> >> Where n identifies the network bits and h identifies the host bits.
> >>
> >> 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh
> >>
> >> 7 First bit is set to 0; Therefore there
> >> are 7 network bits; 24 host bits
> >>
> >> 7 First octet: 0 - 127
> >>
> >> 7 126 Class As exist (0 and 127 are
> >> reserved)
> >>
> >> 7 16,777,214 hosts on each Class A
> >>
> >> Note the most significant bit of the first octet is set to a binary 0 ,
> >> the rest of the bits in the first octet can be zeros or ones, therefore,
> if
> >> the most significant bit of the first octet is 0 it must be class A.
> The
> >> prefix-list picks on the first bit by using a /1 prefix-length.
> >>
> >>
> >>
> >> Class A networks that are or are not subnetted:
> >>
> >>
> >>
> >> R2(config)#ip prefix-list Class-A seq 5 permit 0.0.0.0/1 ge 8 le 32
> >>
> >>
> >>
> >> Note in this case the prefix-list picks on class A, with a prefix-length
> >> of greater than or equal 8 and less than or equal 32, which means that
> all
> >> major class A networks, plus all class A networks that are subnetted.
> >>
> >>
> >>
> >> *
> >> On Wed, Jun 1, 2011 at 1:45 PM, Hammer cisco <cisco.iers_at_gmail.com
> >wrote:
> >>
> >>> thanks danel ,
> >>>
> >>> but still i need to know exactly what's the difference between
> 0.0.0.0/1ge
> >>> 8 and 0.0.0.0/1 le 32
> >>>
> >>> as i think all class A networks starting from mask 8 and greater , i
> have
> >>> not seen a network with mask less 8
> >>>
> >>> On 1 June 2011 23:35, Daniel Kutchin <daniel_at_kutchin.com> wrote:
> >>>
> >>> > If you just want to match Class A's with 8 bit masks, Class B's with
> 16
> >>> bit
> >>> > masks, and class C's with 24 bit masks.
> >>> >
> >>> > 0.0.0.0/1 ge 8 le 8
> >>> > 128.0.0.0/2 ge 16 le 16
> >>> > 192.0.0.0/3 ge 24 le 24
> >>> >
> >>> > If you want to match anything in the individual address spaces for
> >>> class
> >>> > A,B, C
> >>> > 0.0.0.0/1 le 32
> >>> > 128.0.0.0/2 le 32
> >>> > 192.0.0.0/3 le 32
> >>> >
> >>> >
> >>> > Class A- binary first bit 0.
> >>> > Class B - binary first two bits 10.
> >>> > Class C - binary first three bits 110.
> >>> >
> >>> > -
> >>> > Daniel
> >>> >
> >>> >
> >>> > -----Original Message-----
> >>> > From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf
> >>> Of
> >>> > Hammer cisco
> >>> > Sent: Mittwoch, 1. Juni 2011 21:38
> >>> > To: ccielab_at_groupstudy.com
> >>> > Subject: Class "A" prefix-list
> >>> >
> >>> > Hi experts,
> >>> >
> >>> > i am a little bit confused about the exact prefix-list we can use to
> >>> match
> >>> > all class A network address routes :
> >>> >
> >>> > ip prefix-list 0.0.0.0/1 ge 8
> >>> >
> >>> > or
> >>> >
> >>> > ip prefix-list 0.0.0.0/1 le 32
> >>> >
> >>> >
> >>> > Blogs and organic groups at http://www.ccie.net
> >>> >
> >>> >
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> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>
> >>
> >> --
> >> *Narbik Kocharians
> >> *CCSI#30832, CCIE# 12410 (R&S, SP, Security)
> >> www.MicronicsTraining.com <http://www.micronicstraining.com/>
> >> Sr. Technical Instructor
> >> *Ask about our FREE Lab Voucher with our Boot Camps*
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> >>
> >
>
>
> --
> *Narbik Kocharians
> *CCSI#30832, CCIE# 12410 (R&S, SP, Security)
> www.MicronicsTraining.com <http://www.micronicstraining.com/>
> Sr. Technical Instructor
> *Ask about our FREE Lab Voucher with our Boot Camps*
> YES! We take Cisco Learning Credits!
> Training & Remote Racks available
>
>
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>
> _______________________________________________________________________
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Received on Thu Jun 02 2011 - 10:57:22 ART