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For example here is an ip address:

ip address:192.168.0.205

subnet mask:255.255.0.0

broadcast address:192.168.255.255

network address:192.168.0.0

My question is what does 192.168.255.255 do and what does 255.255.255.255 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(255.255.255.255) eliminates them?

Thanks

samir imtiaz
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  • https://networkengineering.stackexchange.com/questions/37571/broadcasting-traffic-by-255-255-255-255-or-by-subnet-dot-all-ones?rq=1 – mere3ortal Apr 03 '18 at 10:22
  • Please help me to explain my next question's answer. – samir imtiaz Apr 03 '18 at 10:33
  • See _[RFC 2644, Changing the Default for Directed Broadcasts in Routers](https://tools.ietf.org/html/rfc2644)_ for the reasons that routing directed broadcasts are a security problem. – Ron Maupin Apr 03 '18 at 15:19

1 Answers1

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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 192.168.0.15 is a broadcast address for a /28 but not /24 network.

A router connected to 192.168.0.0/28 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.

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jonathanjo
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