RE: Prefix-list

From: Scott Morris (smorris@ipexpert.com)
Date: Thu Nov 29 2007 - 10:40:10 ART


128 = 10000000
      ^^ the bits covered by /2.

191 = 10111111 keeps the same two first bits (unchanged)

192 = 11000000 which wanders off the reservation... (It won't be covered no
matter what you permit for the mask length with ge or le)

HTH,

Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE-M
#153, JNCIS-ER, CISSP, et al.
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-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Fernando Carvalho
Sent: Thursday, November 29, 2007 7:54 AM
To: 'vignesh sethuraman'; ccielab@groupstudy.com
Subject: AW: Prefix-list

Hi,
ip prefix-list <name> permit 128.0.0.0/2 ge 3 le 32 will do it.
Basically you are specifying your network as 128.0.0.0/2 and identifying all
the "subnets" from this network with subnetmask between 3 and 32 bits that
means covering all until 192.255.255.255.

HTH

-----Urspr|ngliche Nachricht-----
Von: nobody@groupstudy.com [mailto:nobody@groupstudy.com] Im Auftrag von
vignesh sethuraman
Gesendet: Donnerstag, 29. November 2007 12:09
An: ccielab@groupstudy.com
Betreff: Prefix-list

Hello,
   
  I need to permit only class B addresses (128.0.0.0 - 191.255.255.255)
using prefix list. I used
   
  ip prefix-list <name> permit 128.0.0.0/2 ge 16 le 24
   
  Will the above command will stop permitting for example 192.0.0.5/24
   
  If it is so could someone explain how that works.
   
  Thanks,
  Vignesh
   

       
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