Re: OT: 5.20 EIGRP Filtering with Prefix-Lists

Which lab are we talking about?

Anyway, the first part of the prefix-list (30.0.0.0/14 or 31.0.0.0/14)
sets the range for the addresses. So any network from 30.0.0.0 to
30.3.255.255 and 31.0.0.0 to 31.3.255.255 would be CONSIDERED by the
prefix-list.

Once a route is considered, then the mask is looked at next. And in
this case, the vlsm mask for the route must be Greater than or Equal to
16 bits AND Less than or Equal to 16 bits. Which pretty much means it
must be 16 bits. :) So you're only matches then would be:

30.0.0.0/16
30.1.0.0/16
30.2.0.0/16
30.3.0.0/16

31.0.0.0/16
31.1.0.0/16
31.2.0.0/16
31.3.0.0/16

HTH,

*Scott Morris*, CCIE/x4/ (R&S/ISP-Dial/Security/Service Provider) #4713,

JNCIE-M #153, JNCIS-ER, CISSP, et al.

JNCI-M, JNCI-ER

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Nadeem Rafi wrote:
> posted few weeks ago on INE forums but no reply so have to post it here.
>
> what does this means?
>
> ip prefix-list STOP_RIP_SUBNETS seq 5 deny 30.0.0.0/14 ge 16 le 16
> ip prefix-list STOP_RIP_SUBNETS seq 10 deny 31.0.0.0/14 ge 16 le 16
>
> I know that 30.0.0.0/14 is required network to be used but why ge 16 le 16
> is used?
>
>
>
> Any good source for understanding prefix-lists ?
>
>
>
> Thanks in advance for any help.
>
>
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Received on Fri Jul 24 2009 - 07:26:19 ART