Route-map Access-list Q

[newnetman]

Hello All,

Can someone please clarify as to why and when a second line of route-map requires a permit statement when the first line is already a permit statement?

I have seen this in many books but confuses me.

As for an access-list i know if the first statement is deny, there is a need for a second line to permit if one desires other prefixes to do otherwise.

Hope someone can help me sooner?.

Thanks

[Edison Ortiz]

A second route-map line is needed since there is an implicit deny.

For instance, on BGP - you may have routes you want to change the AS_PATH so you create a route-map permit 10 with a match against those routes but other routes should also be sent by BGP with the AS_PATH unchanged so you create another route-map with permit 20. If you don't create a second route-map, routes not matching on permit 10 won't be advertised by BGP.

HTH,

__

Edison.