From: Dillon Yang (gzdillon@hotmail.com)
Date: Tue Mar 29 2005 - 12:40:32 GMT-3
Yes, Sundar:
The task is just the SIX routes!
so feel free.
I think you'd not overthink the unknown subnet as 3, 6, 7.
Any expert advice?
HTH
dillon
----- Original Message -----
From: "Sundar Palaniappan" <sundarp@gmail.com>
To: "Philippe Couture" <philippecouture@gmail.com>
Cc: <ccielab@groupstudy.com>; <Lee.Donald@t-systems.co.uk>
Sent: Tuesday, March 29, 2005 11:28 PM
Subject: Re: IP Prefix-list Question
> Dillon,
>
> You are allowing subnets 3, 6, 7 that aren't part of the requirment.
>
> Lee's requirement is minimum number of lines to be used. Your solution
> would be correct if only one line is to be used to accomplish that.
>
> Not sure if Cisco would consider your solution correct.
>
> --Sundar Palaniappan
>
>
> On Tue, 29 Mar 2005 10:23:04 -0500, Sundar Palaniappan
> <sundarp@gmail.com> wrote:
> > My bad.
> >
> > Last statement should be,
> >
> > ip prefix-list cisco permit 192.54.4.0/23 ge 24 le 24
> >
> > What you are doing is, you are permiting everything after
> > 192.54.4.0/23 but the subnet mask has to be 24 bits always.
> >
> > If you don't use le 24 then you are allowing prefixes with shorter
> > mask i.e .25, .26 etc to be advertised.
> >
> > In the lab, I wouldn't take a chance and just nail it down.
> >
> > HTH,
> > Sundar Palaniappan
> >
> >
> > On Tue, 29 Mar 2005 10:03:43 -0500, Philippe Couture
> > <philippecouture@gmail.com> wrote:
> > > Sundar,
> > >
> > > Wouldn't the third line need to be "ip prefix-list cisco permit
> > > 192.54.4.0/23 ge 24" ?
> > >
> > > I could be wrong but I think that since you don't care about the 24th
> > > bit (i.e. you want to match .4 and .5), you would use a mask length of
> > > 23, and the "ge 24" says to use prefix lengths of 24 or more. If you
> > > want to really only allow 24 and nothing longer, you would also need
> > > to add "le 24".
> > >
> > > Phil
> > >
> > >
> > > On Tue, 29 Mar 2005 09:54:59 -0500, Sundar Palaniappan
> > > <sundarp@gmail.com> wrote:
> > > > Lee,
> > > >
> > > > Or you could you configure
> > > >
> > > > ip prefix-list cisco permit 192.54.1.0/24
> > > > ip prefix-list cisco permit 192.54.2.0/24
> > > > ip prefix-list cisco permit 192.54.4.0/24 ge 23
> > > >
> > > > Either way you need 3 statements atleast.
> > > >
> > > > HTH,
> > > > Sundar Palaniappan
> > > >
> > > > On Tue, 29 Mar 2005 15:19:12 +0100, Lee Donald
> > > > <Lee.Donald@t-systems.co.uk> wrote:
> > > > > I'm having trouble understanding IP Prefix-lists can anybody clarify this
> > > > > for me?
> > > > >
> > > > > I have this question; use a prefix list with the minimum amount of lines to
> > > > > allow 1,2,4,5 networks in.
> > > > >
> > > > > 192.54.1.0/24
> > > > >
> > > > > 192.54.2.0/24
> > > > >
> > > > > 192.54.4.0/24
> > > > >
> > > > > 192.54.5.0/24
> > > > >
> > > > > 192.54.21.0/24
> > > > >
> > > > > 192.54.22.0/24
> > > > >
> > > > > I have 3 lines, 2 denying 21, and 22, the other allowing everything.
> > > > >
> > > > > Is this the minimum?, if not why not?
> > > > >
> > > > > Thanks in advance for your help.
> > > > >
> > > > > Regards
> > > > >
> > > > > Lee Donald.
> > > > >
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