Hello fly,
it depends on the order of operations performed inside the router possible cases are the following:
a) if port mirroring happens before uRPF action you should get all packets arriving at the source interface either matching uRPF either failing uRPF check
b) if port mirroring happens after uRPF action you should get in packet capture only packets that pass uRPF check
c) if the two features are not compatible you may get no packets on the wireshark protocol analyzer.
What do you see on the sniffer ?
Hope to help
Giuseppe
