Public Subnet re-assignments

First, sorry if this is a bit of a noob question. I'm trying to find a way of preventing a slew of traffic to an IP, or IP's, when I join two /30 public subnets to a /29. It appears that while the ranges are /30 someone is trying to brute-force the network and/or broadcast addresses for the ranges. When I change them to be a /29, now the router sees the traffic and starts dropping packets. Are there any suggestions for mitigating this behavior or is it just the nature of the beast? -- 101010