From: Jay Hennigan (jay@west.net)
Date: Thu Jun 05 2003 - 12:58:46 GMT-3
On Thu, 5 Jun 2003, OhioHondo wrote:
> The requirement is to allow only 192.168.1.0/24, 192.168.2.0/24
> and 192.168.5.0/24 ONLY
>
> > prefix-list XXX seq 5 permit 192.168.0.0/21 ge 24 le 24
>
> This will allow 192.168.0.0/24 through 192.168.7.0/24 and nothing else.
Correct. The premise begins...
AS 254 is advertising five routes to R4 in the range...
192.168.1.0/24
192.168.2.0/24
192.168.5.0/24
192.168.20.0/24
192.168.21.0/24
The requirement is to allow only 192.168.1.0/24, 192.168.2.0/24
and 192.168.5.0/24 ONLY; and filter all other routes. DO NOT use
any access-lists / distribute lists; use only prefix lists with
minimum number of lines.
So given this premise, the single line will meet the requirement.
If AS254 were also advertising 192.168.3.0/24, for example, then it
would be necessary to add additional lines.
-- Jay Hennigan - CCIE #7880 - Network Administration - jay@west.net WestNet: Connecting you to the planet. 805 884-6323 WB6RDV NetLojix Communications, Inc. - http://www.netlojix.com/
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