From: Josh Covarrubias (shmokin@gmail.com)
Date: Fri Jul 25 2008 - 15:50:29 ART
Hey Yung,
Here's some links given to me by Dar-by back in the days that helped me out.
http://www.internetworkexpert.com/resources/01700370.htm
http://www.rhyshaden.com/ipadd.htm
http://isptools.sourceforge.net/calcmask.html
http://www.opennet.ru/soft/cisco-configuration.html
Don't forget all evens and all odds:
0.0.0.0 0.0.0.254 = evens
0.0.0.1 0.0.0.254 = odds
0.0.0.0 0.0.254.0 = evens
0.0.1.0 0.0.254.0 = odds
--------------------------------------------
The way I was taught to do it:
8 has binary = 00001000... so all possible combinations (making those bits
on/off) = 0 & 8
Thus matched subnets become:
151.15.112.0 &
151.15.(112+8).0 or 151.15.120.0.
Now if the wildcard was 0.0.7.255
7 has binary = 00000111, taking the last 3 bits, combinations are 0, 001,
010, 011, 100,101,110,111 or decimal 0,1,2,3,4,5,6,7
so, matching subnets become:
151.15.(112+0).0 or 151.15.112.0
151.15.(112+1).0 or 151.15.113.0
151.15.(112+2).0 or 151.15.114.0
151.15.(112+3).0 or 151.15.115.0
...etc
Regards,
Josh
On Fri, Jul 25, 2008 at 11:07 AM, Yung Li <yungli2008@gmail.com> wrote:
> how do we calculate the allowed routes from the network and wildcard mask
> 151.15.112.0 0.0.8.255?
>
> Would you please any one guide me?
>
> Thanks
>
> Li
>
> On Fri, Jul 25, 2008 at 8:02 PM, kang lee <kanghlee@gmail.com> wrote:
>
> > I think you mean 151.15.112.0 ~151.15.120.0 ?
> >
> > This is the subnet I want to filter but when I did AND and XOR
> calculation,
> > it is coming out 151.15.112.0 0.0.15.255.
> >
> > I was not sure if I did correct calculation.
> >
> > 0 1 1 1 0 0 0 0
> >
> > 0 1 1 1 0 0 0 1
> >
> > 0 1 1 1 0 0 1 0
> >
> > 0 1 1 1 0 0 1 1
> >
> > 0 1 1 1 0 1 0 0
> >
> > 0 1 1 1 0 1 0 1
> >
> > 0 1 1 1 0 1 1 0
> >
> > 0 1 1 1 0 1 1 1
> >
> > 0 1 1 1 1 0 0 0
> >
> >
> >
> > subnet
> >
> > and
> >
> > 0 1 1 1 0 0 0 0
> >
> >
> > 112
> >
> >
> >
> > wildcard
> >
> > Xor
> >
> > 0 0 0 0 1 1 1 1
> >
> > 15
> >
> >
> >
> >
> > thanks
> >
> > On Fri, Jul 25, 2008 at 11:45 AM, lei tian <again.tl@gmail.com> wrote:
> >
> > > 151.25.112.1 - 151.25.112.255
> > > and
> > > 151.25.120.1 - 151.25.120.255
> > >
> > >
> > > On 7/25/08, Sadiq Yakasai <sadiqtanko@gmail.com> wrote:
> > >
> > >> 151.25.112.1 through 151.25.119.255
> > >>
> > >> Is that right guys?
> > >>
> > >>
> > >>
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