RE: help with complex wildcard masks

From: Clay K Auch (clauch) (clauch@cisco.com)
Date: Tue Oct 02 2007 - 18:33:01 ART


Joe,

Sorry about that ... Knee-jerk type reaction. I am working on the solution as well ... For I have also had many hours of fun with these sort of tasks (and obviously continue to do so):<grin>

I am taking a stab ... But, below is what I believe the answer is (please correct if I am missing something .. Have not bee sleeping a lot lately):

        access-list 1 permit 10.1.0.0 0.31.255.255
        access-list 1 permit 10.21.2.0 0.127.239.255

Wow ... Brain fart today ...

Have not lab'd this one up yet. What did you come up with?

Clay
  
-----Original Message-----
From: Joseph Brunner [mailto:joe@affirmedsystems.com]
Sent: Monday, October 01, 2007 10:50 PM
To: Clay K Auch (clauch); 'Cisco certification'
Subject: RE: help with complex wildcard masks

I agree, I was referring to that link when I said I knew how to do those tasks in that link.

This link has not yet yield a strategy to tackle questions like this one...

"Permit 10.1.0.0/24 through 10.128.16.0/24. Do not permit 10.21.1.0/24. Do not use any deny statements. Use as few lines a possible, yada yada yada."

See?

Help :(

-----Original Message-----
From: Clay K Auch (clauch) [mailto:clauch@cisco.com]
Sent: Monday, October 01, 2007 10:49 PM
To: Joseph Brunner; Cisco certification
Subject: RE: help with complex wildcard masks

Hello Joseph,

I highly recommend this link below. They have laid out the information in
such a way that allows you to understand it by the end of the read.

http://www.internetworkexpert.com/resources/01700370.htm

Enjoy!

Clay
 
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Joseph Brunner
Sent: Monday, October 01, 2007 9:08 PM
To: 'Cisco certification'
Subject: help with complex wildcard masks

Good evening (or morning/afternoon if you are east of ZULU time),

 

I was wondering if someone can point me to a good source of information for
calculating complex wild card masks. I'm very fast/accurate and
anding/xoring a few

Ip addresses and coming up with an ip address and a discontinuous-ones wild
card mask to permit several addresses on one acl line thanks to the Brians's
nice paper we all see here often. I'm more interested in things like this.

 

Match 10.0.1.0/24 through 10.248.0.0/24 in as few acl lines as possible.

 

What is the trick to calculation of the wild card masks? I often see weird
answers here and there that wont match a few subnets from that group (say
3), then they bundle them in to make 4 or 5 lines to solve the above
question.

 

I would really appreciate some direction here.

 

Thanks,

 

Joseph Brunner



This archive was generated by hypermail 2.1.4 : Fri Nov 16 2007 - 13:11:11 ART