Well I guess you'd like to ask what actually does rather than what might exit the interface towards the ISP to whom you are pointing the default route to. As the list of all allocated prefixes minus the list of prefixes you accept from the other ISPs will only get you all the possibilities rather than actual destinations used by your customers. So I guess the only way to really find out what destinations are covered by the default route is enabling netflow/sflow on the particular interface and analyze the captures.
adam -----Original Message----- From: cisco-nsp [mailto:[email protected]] On Behalf Of Jeffrey G. Fitzwater Sent: Tuesday, July 02, 2013 11:01 PM To: Saku Ytti Cc: <[email protected]> Subject: Re: [c-nsp] How to tell what routes are not in CEF and follow DEFAULT path? I have 0.0.0.0 pointing to one of our ISP so that any prefix < /24 ( which we don't permit in from any ISP) would get pushed to that ISP which might have route. I am just trying to figure out how may are being pushed to default. Jeff F. On Jul 2, 2013, at 4:53 PM, Saku Ytti <[email protected]> wrote: > On (2013-07-02 20:19 +0000), Jeffrey G. Fitzwater wrote: > >> I would like to find out what routes are NOT in my route table and therefore follow the DEFAULT path to 0.0.0.0. >> >> Would "show ip cef unresolved" work ? I get nothing back when I run it but maybe there is nothing to see. > > What you imagine is FIB covering all possibilities and then next-hop > or null, it would not scale and makes no sense. 0.0.0.0 is branch when > there is no matching top-level branch. > > You could produce such data offline and aggregate it to maximally. > > -- > ++ytti > _______________________________________________ > cisco-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/ _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/ _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
