Is it possible to stop a non-ABR from advertising out a single subnet to other routers?
i.e.: in the below diagram, can the LAN 10.1.1.1/24 be advertised down Rtr1 path, but not Rtr2 path? Rtr1 and Rtr2 area both in area 203 and have an adjacency using 126.96.36.199 network; RRA and RRB are ABRs in area 203 and area 0. There are other sites connected to RRA and RRB in area 203 that I do not want to have knowledge of 10.1.1.1/24 if the Rtr1 WAN link was to go down.
LAN prefix1: 10.1.1.1/24
LAN prefix2: 188.8.131.52/24
Distribute-lists only stop prefixes being learned by the next-hop router, but it will still forward on the LSA to downstream routers who will learn the subnet.
Filter-lists are mainly for inter-area route filtering and would need to be applied across all ABRs in the same area. But if I wanted to stop a prefix being advertised intra and inter area, this doesn't work.
Rtr2 will learn both LAN prefixes from Rtr1. Is there a way to stop Rtr2 advertising out 10.1.1.1/24 to RRB?