From: Mingzhou Nie (mnie@xxxxxxxxx)
Date: Sat Aug 17 2002 - 12:10:42 GMT-3
I will go for either of following two.
access-list 10 permit 128.0.0.0 63.255.255.255
ip prefix-list k seq 10 permit 128.0.0.0/2 le 32
--- Khalid Siddiq <khalid@sys.net.pk> wrote:
> Dear all,
> please don,t use these types of hard words,its look like some kind of
> professional jealousy.
> i have tested this prefix-list in my lab and its working fine.
>
>
> Class A : ip prefix-list k seq 5 permit 0.0.0.0/1 ge 8 le 8
> Class B : ip prefix-list k seq 10 permit 128.0.0.0/2 ge 16 le 16
> Class C : ip prefix-list k seq 15 permit 192.0.0.0/3 ge 24 le 24
>
>
> Please correct if i miss something.
> regards,
> khalid
> -----Original Message-----
> From: EbonyGuru@aol.com [mailto:EbonyGuru@aol.com]
> Sent: Friday, August 16, 2002 4:29 AM
> To: brian@cyscoexpert.com; chaimgev@hotmail.com;
> ciscojunkie@teamhealth.com; ccielab@groupstudy.com
> Subject: Re: IP PREFIX-LIST HELP!
>
>
> Hey Brian,
>
> Surely you know it is dangerous to play mental games with someone
> that has
> been sucked into the mental vortex thatis called 2 days before your
> lab.
>
> So, thanks for your help but you must finish what you started.
>
> I believe what you meant to type was the following:
>
> Ip prefix-list CLASS_A permit 0.0.0.0/0 ge 0 le 8
>
> and not:
>
> Ip prefix-list CLASS_A permit 0.0.0.0/1 ge 8 le 8 --- please comment
> on my
> correction.
>
> You have been a great help so far so now please do one of two things,
> finish
> all the classes or refer me to a reliable reference.
>
> So you dont think I am lazy, this is my revised idea of class B
> filter:
>
> ip prefix-list CLASS_B permit 128.0.0.0/8 ge 8 le 16 ....and so on.
>
> Class C:
>
> ip prefix-list CLASS_B permit 192.0.0.0/16 ge 16 le 24
>
> correct, or way off?
>
> Now bro, end this and quit playing---- :-)
>
> TIA,
>
> E'Guru
>
>
> In a message dated 15/08/2002 14:39:06 GMT Daylight Time,
> brian@cyscoexpert.com writes:
>
>
> > Subj:RE: IP PREFIX-LIST HELP!
> >
> >
> > Unfortunately no one has gotten it right in this thread yet.
> If
> > you write out the classes in binary, you can see that all class A
> > addresses start with a 0 (most significant bit), all class B with
> 10,
> > class C, 110, class D 1110, class E 1111. It's the first 4 most
> > significant bits that determine the class of an address.
> >
> > To match on classful networks, we not only have to match on the
> > prefix, but also the prefix-length. Therefore, to accept only
> classful
> > networks, all class A's would have to have a mask of 8, B 16, C 24,
> etc.
> > This can be accomplished with either a prefix-list or an extended
> > access-list. Suppose we are matching class A addresses. The first
> bit
> > must be 0, and the mask must be 8.
> >
> > Ip prefix-list CLASS_A permit 0.0.0.0/1 ge 8 le 8
> > access-list 100 permit 0.0.0.0 127.0.0.0 host 255.0.0.0
> >
> > The prefix-list syntax reads:
> >
> > Check against the first bit of 0.0.0.0
> > The mask is greater than or equal to 8
> > The mask is also less than or equal to 8 (exactly 8)
> >
> > Access-list syntax reads basically the same.
> >
> > Check the first bit, it must be 0
> > The mask is exactly 8
> >
> > I don't want to spoil all the fun, so let's see if you guys can
> come up
> > with the syntax for class B and class C.
> >
> > HTH
> >
> > Brian McGahan, CCIE #8593
> > Director of Design and Implementation
> > brian@cyscoexpert.com
> >
> > CyscoExpert Corporation
> > Internetwork Consulting & Training
> > http://www.cyscoexpert.com
> > Voice: 847.674.3392
> > Fax: 847.674.2625
> >
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
> Behalf Of
> > Chaim Gev
> > Sent: Thursday, August 15, 2002 7:51 AM
> > To: ciscojunkie@teamhealth.com; EbonyGuru@aol.com;
> > ccielab@groupstudy.com
> > Subject: Re: IP PREFIX-LIST HELP!
> >
> > and what about subnets of the callas B networks?
> >
> >
> > >From: "CiscoJunkie" <ciscojunkie@teamhealth.com>
> > >Reply-To: "CiscoJunkie" <ciscojunkie@teamhealth.com>
> > >To: <EbonyGuru@aol.com>, <ccielab@groupstudy.com>
> > >Subject: Re: IP PREFIX-LIST HELP!
> > >Date: Thu, 15 Aug 2002 07:59:47 -0400
> > >
> > >I hate to sound TOO logical, but if you are asked to "filter all
> class
> > B
> > >nets" (allow in our deny them in??), would it not simply just be:
> > >
> > >"ip refix-list zib seq 10 (permit or deny) 0.0.0.0/16"
> > >
> > >----- Original Message -----
> > >From: <EbonyGuru@aol.com>
> > >To: <ccielab@groupstudy.com>
> > >Sent: Thursday, August 15, 2002 4:57 AM
> > >Subject: IP PREFIX-LIST HELP!
> > >
> > >
> > > > Hey Guys,
> > > >
> > > > Can someone please help me check if this is correct:
> > > >
> > > >
> > > > To filter all class B nets:
> > > >
> > > > ip prefix-lis zib seq 10 permit 0.0.0.0/0 ge 16 le 24
> > > >
> > > > Please also tell me where to find a reference with
> configuration
> > >examples.
> > > >
> > > > TIA.
> > > >
> > > > E'Guru
> > > >
This archive was generated by hypermail 2.1.4 : Sat Sep 07 2002 - 19:48:27 GMT-3