From: Nick Shah (nshah@xxxxxxxxxxxxxx)
Date: Fri Jun 14 2002 - 01:40:53 GMT-3
Elping,
say you want to block 200.200.x.x/24, then you would use 200.200.0.0/16 ge
24 le 24
the mask /16 saying you are matching the first 2 octets, and ge24 le24
guarantees that ur prefix is /24
if you use just 200.200.0.0/16 ge 24 - it permits/denies all 200.200.x.x/24
and above /25,/26 etc.
if you use just 200.200.0.0/16 le 24 - it permits / denies all
200.200.x.x/24 and below /23 , /21 etc. upto /16
so basically mask < ge < le
Few more examples...
block/permit 200.200.x.x prefix between /24 & /28 ----> 200.200.0.0/16 ge 24
le 28
block/permit any prefix smaller than /24 --- > 0.0.0.0/0 le 24
block/permit default gateway (0.0.0.0) -----> 0.0.0.0/0
block/permit any any -----> 0.0.0.0/0 le 32
permit/deny host routes ----> 192.168.1.1/32 (these are easy)
There is a generic explanation on this url..
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fipr
_c/ipcprt2/1cfbgp.htm#1002814
check out same url on the doc cd as well.
rgds
Nick
----- Original Message -----
From: "elping" <elpingu@acedsl.com>
To: <ccielab@groupstudy.com>
Sent: Friday, June 14, 2002 1:53 PM
Subject: prefix-list
> i have been configuring prefix-list and am i having a hard time....
> i am trying to block all /24 in network 200.200.x.x
>
> ip prefix-list 2 seq 5 deny 200.200.0.0/24
> it does not work
>
> i have tryed
> ip prefix-list 2 seq 5 permit 200.0.0.0/24
> stilll does not work
>
> what i am doing wrong ....?
> can someone xplain prefix-list
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