For example here is an ip address:

ip address:

subnet mask:

broadcast address:

network address:

My question is what does do and what does do? Both of them are broadcast addresses.What is their unique usage?

What are the security problems that ip directed broadcast faces and how physical player broadcast( eliminates them?



1 Answer 1


Consider the directed broadcast coming from outside a local network.

As the routers forwarding the packet don't have the network mask (of the far end) it is not possible to identify a directed broadcast IP address. For example is a broadcast address for a /28 but not /24 network.

A router connected to might or might not accept the incoming packet and broadcast it. See for example RFC 2644 on this topic.

Also remember that there are critical layer matters in broadcasting, from the point of view of switches and media transmission in general. See for example my answer here.

Not the answer you're looking for? Browse other questions tagged or ask your own question.