From: Michael Snyder (msnyder@theedgepc.net)
Date: Sat Oct 04 2003 - 11:35:27 GMT-3
I got a problem from the XOR operations below.
"For multiple arguments, XOR is defined to be true if an odd number of
its arguments are true, and false otherwise. This definition is quite
common in computer science, where XOR is usually thought of as addition
modulo 2."
Yet below, there's examples of even number xor operations giving
producing an one.
What's the deal?
-----Original Message-----
From: Ken.Farrington@barclayscapital.com
[mailto:Ken.Farrington@barclayscapital.com]
Sent: Saturday, October 04, 2003 8:16 AM
To: ccielab@groupstudy.com
Cc: bmcgahan@internetworkexpert.com; JKleberg@glhec.org;
derekgaff@eircom.net
Subject: RE: Computing Access-List and Wildcard Pairs (was RE: Wildcard
Ma sks)
Can I just say a Special thx to Derek, Jason and Brian for this.
Excellent stuff, and lets face it, everyone has to master this if you
are to
take your lab.
I encourage others to look at what these canys have posted here.
Many thx all
---------------------
THE RESULTS ARE IN :) (not yet for arsenal - but whey hey, Pires, what
a
goal)
---------------------
121.10.17.0 /24
127.24.6.0 /24
122.35.35.0 /24
111.16.6.0 /24
so result of this particular range is
104.0.0.0 mask 23.59.55.255
Hope this is correct.
*** *
121 01111001
127 01111111
122 01111010
111 01101111
-----------------
Sub-AND 01101000 104
Msk-XOR 00010111 23
** *
10 00001010
24 00011000
35 00100011
16 00010000
-----------------
Sub-AND 00000000 0
Msk-XOR 00111011 59
** *
17 00010001
6 00000110
35 00100011
6 00000110
-----------------
Sub-AND 00000000 0
Msk-XOR 00111011 55
but dont apply this as anything can match so normal rules apply .255 not
.0
in the mask
********
0 00000000
0 00000000
0 00000000
0 00000000
-----------------
Sub-AND 00000000
Msk-XOR 00000000
-----Original Message-----
From: Brian McGahan [mailto:bmcgahan@internetworkexpert.com]
Sent: 03 October 2003 22:37
To: Ken.Farrington@barclayscapital.com; ccielab@groupstudy.com
Subject: Computing Access-List and Wildcard Pairs (was RE: Wildcard
Masks)
Ken,
What a coincidence! I have recently written a white paper on
this exact subject! ;)
Computing Access-List and Wildcard Pairs:
http://www.internetworkexpert.com/resources/01700370.htm
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987
Direct: 708-362-1418 (Outside the US and Canada)
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Ken.Farrington@barclayscapital.com
> Sent: Friday, October 03, 2003 5:53 AM
> To: ccielab@groupstudy.com
> Subject: Wildcard Masks
>
> Hello,
>
> Does anyone have any comprehensive documentation on complex
wildcarding
> for
> spurious networks, ie
>
> 192.168.10.0/24
> 172.16.40.128/25
> 10.1.2.0/16
> 141.226.50.0/24
>
> Say I wanted to use an ACL with a wildcard mask to cover these
networks
> with
> the minimum configuration.
>
> Believe it or, not, it is really hard to find complex examples on the
web
> or
> on CCO.
>
> This is very confusing.
>
> Many thx
>
> ________________________________________________________________
> Ken Farrington
> Global Networks, Barclays Capital, 5 The North Colonnade, Canary
> Wharf, London, E14 4BB
> * Tel : 020 7773 3550
> * Mob : 07768-866655
> * ken.farrington@barcap.com
>
>
>
>
>
------------------------------------------------------------------------
> For more information about Barclays Capital, please
> visit our web site at http://www.barcap.com.
>
>
> Internet communications are not secure and therefore the Barclays
> Group does not accept legal responsibility for the contents of this
> message. Although the Barclays Group operates anti-virus programmes,
> it does not accept responsibility for any damage whatsoever that is
> caused by viruses being passed. Any views or opinions presented are
> solely those of the author and do not necessarily represent those of
the
> Barclays Group. Replies to this email may be monitored by the
Barclays
> Group for operational or business reasons.
>
>
------------------------------------------------------------------------
>
> ***Get your CCIE and a FREE vacation: Shop.GroupStudy.com***
>
This archive was generated by hypermail 2.1.4 : Mon Nov 24 2003 - 07:52:57 GMT-3