From: marc van hoof (mvh@marcvanhoof.com)
Date: Fri Nov 05 2004 - 01:37:46 GMT-3
ah - ok - i thought that when you said "the /24 applies to both the
network address and the net mask" that you meant the netmask (as well as
the network) had 24 fixed bits and 8 variable bits...
as mentioned later in the post, it wasn't long ago that you had masks for
masks...
misunderstanding - apologies...
cheers,
-marc.
On Thu, 4 Nov 2004, ccie2be wrote:
> No, those 2 prefix aren't the same.
>
> The 1st prefix list means that the 1st 24 bits must equal to 192.168.0 and
> the net mask is 24 bits long.
>
> The 2nd perfix list means that the 1st 24 bits must equal 192.168.0 (same as
> before) but the le 32 that follows means the net mask can be from 24 bits
> long to 32 bits long.
>
> Don't overlook that le means LESS THAN OR EQUAL.
>
> So, the 1st perfix list means 192.168.0.0 255.255.255.0 ONLY/
>
> The 2nd prefix list means the following matches:
>
> 192.168.0.0/24
> 192.168.0.0/25
> 192.168.0.0/26
> 192.168.0.0/27
> 192.168.0.0/28
> 192.168.0.0/29
> 192.168.0.0/30
> 192.168.0.0/31
> 192.168.0.0/32
>
> So, you see there's a big difference.
>
> HTH, Tim
> ----- Original Message -----
> From: "marc van hoof" <mvh@marcvanhoof.com>
> To: "ccie2be" <ccie2be@nyc.rr.com>
> Cc: "Cisco Net" <network.cisco@gmail.com>; "Group Study"
> <ccielab@groupstudy.com>
> Sent: Thursday, November 04, 2004 10:54 PM
> Subject: Re: Prefix lists differences ?
>
>
>> so what you're saying is that if you don't specify the ge xx le xx, it
>> means that you are specifying a minimum mask length ?
>>
>> seems odd, but i'll believe it...
>>
>> basically that would mean that
>>
>> ip prefix-list 10 permit 192.168.0.0/24
>>
>> is the same as
>>
>> ip prefix-list 10 permit 192.168.0.0/24 le 32
>>
>> ??
>>
>> on this topic, do people remember the days before prefix-lists, where you
>> HAD to use extended ip access lists for route filtering, and the
>> "destination address/mask" of the extended acl referred to the mask of the
>> route ?
>>
>> it was never any fun to see:
>>
>> access-list 100 permit 192.160.0.0 0.0.0.255 255.255.255.0 0.0.0.255
>>
>> cheers,
>> -marc.
>>
>> On Thu, 4 Nov 2004, ccie2be wrote:
>>
>>> They're the same.
>>>
>>> The slash 24 in the 1st prefix list means the 1st 24 bits of the network
>>> address must match and the ge 24 le 24 means the net mask must be
> exactly 24
>>> bits.
>>>
>>> In the 2nd prefix list, when you don't have either ge or le, then the
> /24
>>> refers to both the network address and the net mask.
>>>
>>> HTH, Tim
>>>
>>> ----- Original Message -----
>>> From: "Cisco Net" <network.cisco@gmail.com>
>>> To: "Group Study" <ccielab@groupstudy.com>
>>> Sent: Thursday, November 04, 2004 10:20 PM
>>> Subject: Prefix lists differences ?
>>>
>>>
>>>> Hi
>>>> Is the meaning of the following 2 Prefix lists are same ?
>>>> -ip prefix-list ONE permit 100.100.100.0/24 ge 24 le 24
>>>> -ip prefix-list TEO permit 100.100.100.0/24
>>>>
>>>> I thought both are same.. What do you think ?
>>>> Regds
>>>> Cert
>>>>
>>>> _______________________________________________________________________
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>>>
>>> _______________________________________________________________________
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