From: Sundar Palaniappan (sundarp@gmail.com)
Date: Tue Mar 29 2005 - 12:28:51 GMT-3
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.
> > > >
> > > > _______________________________________________________________________
> > > > Subscription information may be found at:
> > > > http://www.groupstudy.com/list/CCIELab.html
> > >
> > > _______________________________________________________________________
> > > Subscription information may be found at:
> > > http://www.groupstudy.com/list/CCIELab.html
This archive was generated by hypermail 2.1.4 : Sun Apr 03 2005 - 17:56:54 GMT-3