02-25-2011 09:02 PM - edited 03-06-2019 03:46 PM
Hi every one
Routers by dedault stop broadcast address.
Let say we have following set-up
Lan----f0-Router-S0--------Wan
F0( ip address) 199.199..199.17 255.255.255.240
Let say router receives a packet on s0 with destination ip 199.199.199.31
what router will do? will it send it out of f0? if yes but it is broadcast address,
thanks and have a great weekend.
02-25-2011 09:41 PM
Hi Sarah,
A packet sent from a remote network to our directly connected network's broadcast IP address 199.199.199.31 is in this case called a directed broadcast. A directed broadcast is routed through intermediate routers just like any other packet. Only when it arrives into the router that has the destination network directly connected, it starts to be slightly more interesting.
What will happen now depends on whether the Fa0/0 (the destination network's interface) has the ip directed-broadcast command applied to it. If yes then the router will simply forward the packet onto the LAN, encapsulated in a broadcast-addressed Ethernet frame. If the command is not applied (which is the default) then the router will drop the packet.
Best regards,
Peter
02-25-2011 10:29 PM
thanks Peter.
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