bit netmaskCisco mask hosts usable hosts Class/4240.0.0.015.255.255.255268435456268435454 /5248.0.0.07.255.255.255134217728134217726 /6252.0.0.03.255.255.255 6710886467108862 /7254.0.0.01.255.255.2553355443233554430 /8255.0.0.00.255.255.2551677721616777214 A Class /9255.128.0.00.127.255.25583886088388606 /10255.192.0.00.63.255.25541943044194302 /11255.224.0.00.31.255.25520971522097150 /12255.240..