I'll assume you intended
access-list 101 permit ip 160.0.0.0 0.255.255.255 255.0.0.0 0.0.0.0
This form of access list is used to filter distibution of routes. The first
number is the network, the second the network's "don't care" bits, the third
is the network mask and the fourth is mask's "don't care" bits.
If this is the entire access list, then all routes other than 160.0.0.0
255.0.0.0 will be filtered from distribution. It isn't apparent why all but
this one route will be filtered. The first don't care bits say 160.*.*.*
networks are ok, but the second set say the mask must only be 255.0.0.0 If
you think about it, only one valid route can pass both conditions. You
can't have a route to 160.10.0.0 with a 255.0.0.0 mask. We could conclude
that the network don't care bits are wrong and should really be 0.0.0.0, but
that's being picky.
The normal application of this type of access list is to allow the
advertisement of a summary route or supernet and filter all of the subnet
routes. Thus reducing the routes advertised and overhead.
Rodgers Moore, CCDP, CCNP-Security
""Yee, Jason"" <[EMAIL PROTECTED]> wrote in message
859B90209E2FD311BE5600902751445D2E7DBF@LYNX">news:859B90209E2FD311BE5600902751445D2E7DBF@LYNX...
> hi,
> anyone knows how to interpret the access-list below :
>
> access-list 101 160.0.0.0 0.255.255.255 255.0.0.0 0.0.0.0
>
>
> Jason
>
>
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