Steve,
The second pair of numbers on the access lists have to do with the mask that
is sent in the routing update.
10.1.1.0 0.0.0.255 255.255.255.0 0.0.0.255
+----------------+
this means network 10.1.1.0 & we don't care what the 4th octet is.
the second part means the mask must be at least 255.255.255.0 and we don't
care what the 4th octet of the mask is.
so if we got an advertisement for 10.0.0.0 mask 255.0.0.0 it would be thrown
out.
now what if my acl looked like this
10.0.0.0 0.255.255.255. 255.255.0.0. 0.0.0.0
this means any network that starts out with a 10 and we don't care about the
rest.
the second part means that only routes with a 255.255.0.0 mask. so all
routes with masks other than 255.255.0.0 are thrown out.
lastly, you have a good example in your config.
access-list 100 permit ip any 255.255.255.128 0.0.0.127
this means we'll accept routes to any network, but only if it is a subnet of
25 bits or more.
Rodgers Moore
""Steve Warner"" <[EMAIL PROTECTED]> wrote in message
008d01c023d9$cd8e3be0$[EMAIL PROTECTED]">news:008d01c023d9$cd8e3be0$[EMAIL PROTECTED]...
> Hi,
>
> Could someone explain what the right hand bit of the extended Access-list
> does below. This is taken from a router running an in-bound route map for
> BGP. This is used to reject routes.
>
>
> Steve
>
>
> route-map peer-in deny 10
> match ip address 100
>
> route-map peer-in permit 20
> set local-preference 100
> set community 1234:80 1234:3000
>
> access-list 100 permit ip 192.41.177.0 0.0.0.255 255.255.255.0 0.0.0.255
> access-list 100 permit ip 198.32.130.0 0.0.0.255 255.255.255.0 0.0.0.255
> access-list 100 permit ip any 255.255.255.128 0.0.0.127
> access-list 100 permit ip host 0.0.0.0 any
> access-list 100 permit ip 127.0.0.0 0.255.255.255 255.0.0.0 0.255.255.255
> access-list 100 permit ip 10.0.0.0 0.255.255.255 255.0.0.0 0.255.255.255
> access-list 100 permit ip 172.16.0.0 0.15.255.255 255.240.0.0 0.15.255.255
> access-list 100 permit ip 192.168.0.0 0.0.255.255 255.255.0.0 0.0.255.255
> access-list 100 permit ip 192.0.2.0 0.0.0.255 255.255.255.0 0.0.0.255
> access-list 100 permit ip 128.0.0.0 0.0.255.255 255.255.0.0 0.0.255.255
> access-list 100 permit ip 191.255.0.0 0.0.255.255 255.255.0.0 0.0.255.255
> access-list 100 permit ip 192.0.0.0 0.0.0.255 255.255.255.0 0.0.0.255
> access-list 100 permit ip 223.255.255.0 0.0.0.255 255.255.255.0 0.0.0.255
> access-list 100 permit ip 198.32.136.0 0.0.0.255 255.255.255.0 0.0.0.255
> access-list 100 permit ip 149.20.0.0 0.0.255.255 255.255.0.0 0.0.255.255
> access-list 100 permit ip 198.32.128.0 0.0.0.255 255.255.255.0 0.0.0.255
> access-list 100 permit ip 192.157.69.0 0.0.0.255 255.255.255.0 0.0.0.255
> access-list 100 permit ip 224.0.0.0 31.255.255.255 224.0.0.0
31.255.255.255
> access-list 100 deny ip any any
>
>
>
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