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New Member

Last subnet verification

Hi, can you just confirm the below is right ?

For ip address assignment, can you confirm my

calculation below for the last subnet is correct ?

Interesting because if I use an IP calculator, when I

get to subnet "" I hit "next subnet" and then

I get I know that may be a silly observation,

but I just want to make sure I am not overlooking anything.

First subnet Broadcast host range (zero) -

Last subnet Broadcast host range -

Number of bits in the subnet identifier:11

Number of possible IP addresses in each subnet:2^11 = 2048


Re: Last subnet verification

you are having subnet and I guess you are further trying to subnet this network. For this you need to tell us that what is the new subnet mask you are using to further subnet this network. hope my understanding is correct else correct me.

say, you are going to further subnet this /19 to /24 network. In this case you will have 32 /24 network each having 254 hosts. remember you can further subnet these /24s into /25 ... /30 depending on your requirement.

hope to helps ... rate if it does ...


Re: Last subnet verification

Hi Marlon

For network

Subnet Address is

Broadcast Address is

Host Range is -

If you are trying to "subnet" this network with 2048 address per subnet, then you will have:

No. Subnet Address Hosts From Hosts To Broadcast Address





Hope this helps

New Member

Re: Last subnet verification

I also got confused by the question.

The book just tells this:

Given the "IP address assignment, what is the first and last subnet? What is the range of hosts for the first and last subnet? ".

Since thet is a class A address, I figured that Subnet Mask bit = 11.

Subnet Mask =

From there I found the data I posted.

If you think my interpretation from the question is wrong, please let me know.

New Member

Re: Last subnet verification

I don't know where you got the Subnet Mask bit=11 from... a /19 network has the subnet mask of

Your network is, which means each subnet has 2^13 usable addresses (32-19), minus wire/broadcast addresses. This equates to 8190 usable per /19 network.

First subnet (assuming ip subnet-zero), will be the, consisting of through

Last subnet will be through

The point to remember is for a /19 network, the first 19 bits cannot change. This makes the first two octets (10.0) easy to calculate, and the third octet just goes up in 32's.


Re: Last subnet verification


caluclations for subnet mask of /19


8 bits + 8bits + 3bits =19 bits

11111111 + 11111111 + 11100000 + 00000000

255 . 255. 128+64+32 . 0

subnet mask for /19 =

to caluclate the different subnets use this simple method

256 -224 = 32

subnet 1 = 0 31 :host range usable(1-30)

subnet 2 = 32 63

subnet 3 = 64 95

subnet 4 = 96 127

subnet 5 =128 159

subnet 6 =160 191

subnet 7 =192 223

subnet 8 =224 255

:host range usable(225-254)

Hope this helps you,



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