Is it possible to apply filter on OSPF interfaces within the same area?

Steve Leung kesteve at
Fri Jan 27 08:53:09 CET 2017


Using OSPF, when receiving some routes from a network interface, by default
all routes will be re-advertised to other interfaces within the same area
without applying the filter rules.

Say in the below example.

protocol ospf myospf {
        table t_ospf;
        import filter ifilter;
        export filter ofilter;
        area 0 {
                interface "eth*" {
                        hello 10; retransmit 2; wait 10; dead 300; cost 10;

Routes received from "eth1" will be _forwarded_ to "eth2" and bypassed all
the filters. Is it possible to configure bird.conf so only some of the
routes will be re-advertised? (aka apply filters to interface within the
same OSPF area)

Creating multiple ospf instance and treat the routes as "external routes"
(so filter will apply) is not a good idea for me because the environment is
quite dynamic, may even have hundreds of dynamic virtual interface, and I
hope I do not need to edit the config file all the time.

Thank you so much for your time.

Best regards,
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