Thanks atomicturtle for the lesson above. Still trying to find out what all that means.ġ.
I have to admit, for now I have to rely on the numbers you told me. I am happy that you wrote them down, instead of only telling me the math. I will look into this, put your both IP things into my Firewall. But sometimes you just have to make the choice for the greater good. And when you ban IP ranges you always risk banning too many people which aren´t responsible for anyone. Problem is, since in Europe most countrys still have dynamic IP´s, you can´t just ban 1 IP, because at the next connection break, we get a new IP and so the ban for someone wouldn´t work. Just want to get some people I know off my Site because I know they cause trouble. Guess that makes me a n00b but well, I don´t have time to learn that while work & family. I never saw IP´s this way.įor me IP range´s is like how i posted them, with the actual IP´s and not put them into bits like you did. Still have to swallow all this to actually understand it. This is because they are used for either defining the network (IE, 10.10.10.0/24 uses 10.10.10.0 to define the network) or for broadcasts on the network (10.10.10.255 is the broadcast IP). 255 as IP addresses, it's not a good idea to use the starting or ending IP's for a netblock. Again since we're playing in Class B (16 bit) network space, we start at 16, and add 3 bits (32 networks) to it: 16 + 3 = 19:Ī 3 bit netmask breaks the network up into 8 pieces:Ĭonfused yet? Oh and for your first question, while you can use. If you started at 89.145.32.0/20, you would be covering the network space from: 89.145.32.1 - 89.145.47.254Īnother way to look at it is a 4 bit netmask breaks the network up into 16 pieces:įor the 2nd net block, I start at the IP 89.145.32.0, and add 32 networks to it. Using the network 89.145.16.0 as a jumping point, if we add 16 networks (or 4 bits) to our class B (16 bits) we get 16 + 4 = 20: We're chopping up a class B (16 bit) network into smaller pieces so we start our math problem at 16. So you need a block of 16 (4 bits) and a block of 32(3 bits) to get (16 + 32) 48. Cheat sheet:įorget about networks for a moment, and just do the math using into the largest group that fits into the above, in your case 89.145.16.0 - 89.145.64.0 is a total of 48 networks. We're dealing with subdividing a 16 bit network (2nd position), so we start all calculations from there. This is because TCP/IP is base 8, dividing each section of an IP address into an octet. Its actually my 2nd least useful skill, my first is I can also read heiroglyphics. Which is probably one of the least useful skills a person can have. So what that means is that in binary this: Short version, the bitmask is a binary representation of a network block. So netmasks can be kind of daunting if you don't understand the guts of tcp/ip.