try the CCENT tomorrow morning and I made the test that you propose.
at question 45, I had the choice between
ip dhcp MYPOOL pool
network 192.168.1.1 255.255.255.0
and
ip dhcp MYPOOL pool
network 192.168.1.0 / 24
as all IOS accept “network subnet subnet-mask” and only some recent bones accept “network subnet prefix-length”, I chose “network 192.168.1.1 255.255.255.0”
but the answer of your test indicates as good answer “network 192.168.1.0 / 24”, alas!
however, in packet tracer, “network 192.168.1.1 255.255.255.0” neither “network 192.168.1.10 255.255.255.0” nor “network 192.168.1.1OO 255.255.255.0” generates an error message (and I am convinced of the have seen on an installation script of a client equipment) and, mathematically, the 3 instructions identify the same subnet.
Can you confirm that “network subnet prefix-length” is a Cisco best practice, and that “network subnet subnet-mask” is deprecated?