Can someone please explain to me what 0/24 means, I understnad it means a range but what range?

I see that one can use: 24.202.11.0/24

Does this block 24.202.11.0 - 24.202.11.24
or
24.202.11.0 - 24.202.11.999


Also what if I wanted to block all of 203.0.? is this correct:
203.0/24

tia
gp

/24 represents the first 24 bits of the IP address. So, each of A.B.C.D is 8 bits, therefore /24 represents the A.B.C of the IP.

24.202.11.0/24 is 24.202.11.0 to 24.202.11.255

to block 203.0.0.0 to 203.255.255.255 you would use 203.0.0.0/8

Hope that helps.

<edit>
Go to www.dnsstuff.com and use their CIDR/Netmask Lookup feature to convert from /x format to real IP ranges
</edit>

Thanks, that helped alot.

gp