*Configure a prefix-list on R1 so that it does not install any updates received from R4 on the VLAN 146 segment.
router ei 100
distribute-list prefix DENY-ALL gateway R4 in FastEthernet0/0
ip prefix-list DENY-ALL seq 5 deny 0.0.0.0/0 le 32
ip prefix-list R4 seq 5 permit 155.1.146.4/32
This works for me - I have no EIGRP routes from 155.1.146.4 after applying this config, and I can't see how it breaks the requirement in any way? (I'm still receiving the routes that originated from BB3, but via R5 instead of R4).
The SG has this for the answer:
router eigrp 100
distribute-list prefix PERMIT_ALL gateway NOT_FROM_R4 in
!
ip prefix-list NOT_FROM_R4 seq 5 deny 155.1.146.4/32
ip prefix-list NOT_FROM_R4 seq 10 permit 0.0.0.0/0 le 32
!
ip prefix-list PERMIT_ALL seq 5 permit 0.0.0.0/0 le 32
Can anyone see an issue with this alternative?