Broadcast to subnet Will a broadcast on a supernet broadcast address reach all the subnets? For example if I sent a broadcast to the address 10.172.255.255, would it affect the clients in the subnet 10.172.2.0/24?

No, directed broadcast only works on the layer-2 segment that it ends up at. A packet to `10.172.255.255` would end up as a broadcast to for example `10.172.255.0/24` or `10.172.255.128/25` or `10.172.254.0/23` or ... etc ... depending on which subnet ends at that address.

And that is assuming that a subnet ends there! If the subnet is `10.172.0.0/15` then `10.172.255.255` is just a normal address in the middle of the subnet.

Because causing broadcasts in a remote network is a great way to do a denial of service attack most networks have disabled directed broadcasts. IPv6 doesn't even have them anymore.