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# Prevention Techniques

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- ## How to prevent being a “bounce site”:

  - Turn off directed broadcasts to subnets with 5 hosts or more
    - Cisco: Interface command “no ip directed-broadcast”
    - Proteon: IP protocol configuration “disable directed-broadcast”
    - Bay Networks: Set a false static ARP address for bcast address
  - Use access control lists (if necessary) to prevent ICMP echo requests from entering your network
    - Probably not an elegant solution; makes troubleshooting difficult
  - Encourage vendors to turn off replies for ICMP echos to broadcast addresses
    - Host Requirements RFC-1122 Section 3.2.2.6 states “An ICMP Echo Request destined to an IP broadcast or IP multicast address MAY be silently discarded.”
    - Patches are available for free UNIX-ish operating systems.

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### Notes: