192.168.100.0 is a network ID for a Class C network of 192.168.x.x.

You can't assign your server that address (or any machine for that matter).  The recommended method is to use the highest address for the router, so in your case 192.168.100.254 would be the router then the next address down for your servers/APs/Switches etc etc.

Whatever you do remember to adjust your DHCP ranges so that your static addresses aren't dished out as responses to DHCP requests.

The reason for starting from the highest address in the network for the router and other kit is that when a device looks for an IP it starts at the top and works it's way down.  So 192.168.x.254 (assuming a 24 bit network mask) would be the first address it finds (as 192.168.x.255 is the broadcast address) and then works it's way down from there, so it's an idea place to stick the default gateway so that it can be found quickly.

<<insert random generic statement about efficiency>>

Regards,
Joe