[c-nsp] BGP Config

[Mark D. Nagel]

info at beprojects.com wrote:

>Isn't "permit nothing" the same as "deny everything"?
>
>  
>
In theory yes, but permit <null> is meaningless.  Your route map 
branches each have to match something to be effective.  If the match 
clause doesn't match anything, then the branch may as well not be 
there.  In the context of route filtering, the route map has to be 
configured to permit those routes you want to let through and deny 
everything else.  You can't simultaneously match "nothing" and then 
permit it.  You have to match something (in this case everything), then 
have your branch action defined to do what you want with that match, in 
this case 'deny', not 'permit'.  As others have said, you can do this 
many other ways -- as-path filter, prefix list, distribution list.  Lots 
of knobs to turn :).

Mark

-- 
Mark D. Nagel, CCIE #3177 <mnagel at willingminds.com>
Principal Consultant, Willing Minds LLC
tel: 714-630-4772, fax: 714-630-4773, web: http://www.willingminds.com/