I know that for addresses like e.g. 192.168.17.5 with 255.255.255.0 subnet mask, address 192.168.17.0 is the network id and 192.168.17.255 is the broadcast address and that valid hosts are from 192.168.17.1 to 192.168.17.254.
I understand why 192.168.17.255 can't be used as a host address since everything sent on this is a broadcast, but I can't understand what 192.168.17.0 is used for?
Is it just a reserved name of the network or is it used for something? Every thing I have read says you can't use it as a host address but not why? Is it just a convention?
Can someone please explain what it is used for and why it can't be a valid host address?