IP directed-broadcast

From: Varghese Thomas (vnthomas2@hotmail.com)
Date: Tue Nov 11 2003 - 15:56:54 GMT-3


Hello

I have following setup with all interfaces disabled for ip direct-broadcast
and routers are running 12.2.15T5

--e0(172.16.1.0/24)-Router1-e1--(172.16.12.0/24)--
e0-Router2---e1(172.16.2.0/24).

When I ping from Router1 to either 172.16.2.0 or 172.16.2.255, Router2
responds and vice-versa; when Router2 pings eihter 172.16.1.0 or 172.16.1.255,
Router1 responds.

I was told the following - If the destination network is directly attached and
ip forward directed-broadcasts is disabled then the router replies on behalf
of the subnet but does not forward the broadcast out onto the subnet.

However I have another router running 12.2.8T5(IP/FW/IDS PLUS IPSEC 3DES)
which does not respond to such broad-cast addresses.

Which is normal behaviour? If it is not normal that router should respond to
such ping request, how can I block it without using specific ACLs?

Thanks in advnace.

Tx n RD



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