Re: ipfw matching (revisited)

2002-11-12 Thread Mark 
- Original Message -
From: "Matthew Seaman" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, November 12, 2002 3:45 PM
Subject: Re: ipfw matching (revisited)


> On Tue, Nov 12, 2002 at 03:06:42PM +0100, Mark wrote:
> > Ok, I constructed the following IP:mask for ipfw to match:
> >
> > 202.43.64.0:255.255.191.0
> >
> > This is supposed to match the range 202.43.64.xx to
> > 202.43.127.xx
>
> Close, but no cigar.  You want:
>
> 202.43.64.0:255.255.192.0  also known as 202.43.64.0/18
>  ^
>
> That matches the addresses from 202.43.64.0 to 202.43.127.255
> inclusive.


Thanks for the explanation. Yes, 191 (1011) would only have bit 6
variable; indeed, I needed 192 (1100), to keep the lower 6 bits
variable. It is clear to me now.

Good thing I asked! :)

- Mark


To Unsubscribe: send mail to [EMAIL PROTECTED]
with "unsubscribe freebsd-questions" in the body of the message

Re: ipfw matching (revisited)

2002-11-12 Thread Matthew Seaman 
On Tue, Nov 12, 2002 at 03:06:42PM +0100, Mark wrote:
> Ok, I constructed the following IP:mask for ipfw to match:
> 
> 202.43.64.0:255.255.191.0
> 
> This is supposed to match the range 202.43.64.xx to 202.43.127.xx

Close, but no cigar.  You want:

202.43.64.0:255.255.192.0  also known as 202.43.64.0/18
  ^

That matches the addresses from 202.43.64.0 to 202.43.127.255
inclusive.

Cheers,

Matthew

-- 
Dr Matthew J Seaman MA, D.Phil.   26 The Paddocks
  Savill Way
  Marlow
Tel: +44 1628 476614  Bucks., SL7 1TH UK

To Unsubscribe: send mail to [EMAIL PROTECTED]
with "unsubscribe freebsd-questions" in the body of the message