Hi.
I’m looking for a way to filter some of OSPF advertisements using firewall instead of route filters. The reason is that one of route filters doesn’t work as expected. How can OSPF packets be matched by advertised prefix? Is there any way?
Thanks
It could be possible with L7 filters, but running such filters will consume a lot of CPU resources and another problem is that OSPF does not send one LSA per packet, so even if you get packet to match you will be dropping all LSAs in that packet. Not to mention that this whole filtering thing will generally break OSPF.
OK, thanks for your reply. It seems that there is no way via firewall filters.
It might be more helpful to understand why you want to filter OSPF?
The reason can be found here: http://forum.mikrotik.com/t/ospf-route-not-being-filtered/123376/1 In this post I have described the problem. Currently nobody has any idea how to filter this problematic route. This is the scenario which you have already had hepled me to implement correctly.