Hello,

I am going for my Network+ N10-006 test this next week and I am having some issues with some subnetting. I need to find faster ways to obtain the following details with IP addresses. I can work them out in the long run, taking a lot of time with converting dotted decimal to binary then comparing the subnet mask to the IP address to find network etc. etc. But the real problem is in my test I will be under the time clock with NO calculator. I have done quite a bit of these and not seeming to get faster at them so I am hoping some of you have some good tricks to help speed it up. I have searched the web too but most of them require excel and calculators which I wont be able to use. Info I need to determine quickly is below.

A random IP, 10.150.174.20/17 (If you know a quicker way to convert to binary instead of lining up the formula and plugging in 1/0 in the following: 128 64 32 16 8 4 2 1, that would also be super helpful!)

Network ID

Broadcast

First Valid IP

Last Valid IP

One other thing that is kind of escaping me that I cannot fully grasp yet. If my number of subnets are quite high, like in a /27 that allows me 32 diferent subnet ranges, with 30 valid addresses in each one minus my ID and Broadcast. When you add those up, it goes above the .254 range for the octet and has to increase the octet prior, correct? If so, is there an easier way to calculate these ranges from ID to Broadcast easier then setting down and writing each range out individually? I also experienced that at some point I will hit mid range at .254 and cannot go higher so does that range just lose the rest of the valid IP's or does it carry over with the octet increase?

I know this is a lot of beginner questions to you guys probably but at 300.00 for my cert test I cannot afford to not know why I am answering something haha. Thanks so much in advance!

I'm going to do my best to help you understand how can you do it quicker, but again require lots of practice.

I need network of this subnet, 10.150.174.20/17Do you see the /17. That's the number you have to pay attention because it tells you where you network start and finish.

now every IP it's equal to 8. Meaning each number has a value of an octet. Example

-- This is my binary, you need to memorize it to catch up with the network.128 64 32 16 8 4 2 110 = 00001010

150= 10010110

172= 10101100

20= 00010100

Now, let's crank it up. (

10.150.174.20 /17)Since we are working with the /17 network that means that we are going to work with the 3rd octet 174 why? becuase that's where the network takes a place. Example 11111111.11111111.10000000

The subnet mask for this network is 255.255.128.0 why? because if you sum this up 128+64+32+8+4+2+1=

255128+64+32+8+4+2+1=255128 " the last number 128 it's because there's no more ones therefore I stopped the count.Remember this 1= to network 0= hosts

So we know the subnet mask is 255.255.128.0 now we need to know the rest:

10.150.174.20 /17

Network ID = 10.150.128.0 -

Broadcast = 10.150.255.255

First Valid IP = 10.150.128.1

Last Valid IP = 10.150.255.254

I am going to break it down for you

Network ID = 10.150.128.0-- Where the heck did I get 128? you wonder.Since I knew the value of my last octet which was equal to 128 I proceed to sum up 128 and gives me a total of 256.

128 is lower than 174 therefore I had to sum up the same value to see if I can get closer to such value. because the fact I couldn't get closer. the value remains as 128 because it belongs to the range of the network 128+128=256.

Broadcast = 10.150.255.255After knowing the total of 128+128=256. we have to deduct -1 to 256 because 256 doesn't belong to the binary values. Giving you a total of 255Broadcast = 10.150.255.255

After knowing the value of the network and broadcast ip Looking for the first and last host will be a cup cake.

First Valid IP = 10.150.128.1

Last Valid IP = 10.150.255.254

I think this doesn't need an explication.

I hope this helps,