Cisco Router Configuration Options
Ip verify unicast reverse-path : confirms packets that arrive should be going back on same interface, otherwise drops
Rate limit ICMP and SYN packets
Filter non-routable address space:
Interface xy
ip access-group 101 in
access-list 101 deny ip 10.0.0.0 0.255.255.255 any
access-list 101 deny ip 192.168.0.0 0.0.255.255 any
access-list 101 deny ip 172.16.0.0 0.15.255.255 any
access-list 101 permit ip any any