IP and subnetting questions help !

dnalight

Wondering if anyone could help me with these questions and explain them to me. I tried doing them but I am not sure if I am doing it right or not.


Q.1


Given these two network IP with the default subnet mask
(Ignore - did it so it wouldn't link )


IP: -134.3.0.0
SM : -255.255.0.0


IP: -4.4.0.0
SM: -255.0.0.0


Divide the network into 4 equal subnets and complete the following


Subnet Address
1st subnet
2nd subnet
3rd subnet
4th subnet
Subnet Mask


1st usable IP address


Last usable IP address


Broadcast Address








Q2. Divide the network into equal subnets such that each subnet can support 30 hosts. Complete the following
(Ignore - did it so it wouldn't link )
IP : -199.101.109.0
SM: -255.255.255.0


IP : -7.100.7.0
SM : -255.0.0.0




Subnet Address
1st subnet
2nd subnet
3rd subnet
last subnet
Subnet Mask


1st usable IP address


Last usable IP address


Broadcast Address







I am confused on how to divide subnets if someones could explain it too me that would be much appreciated

rob42

Did you read this [ IPv4 Subnetting TechNotes ]?

rolando3321

Q.1


Given these two network IP with the default subnet mask
(Ignore - did it so it wouldn't link )


IP: -134.3.0.0
SM : -255.255.0.0


IP: -4.4.0.0
SM: -255.0.0.0

Q2. Divide the network into equal subnets such that each subnet can support 30 hosts. Complete the following
(Ignore - did it so it wouldn't link )
IP : -199.101.109.0
SM: -255.255.255.0


IP : -7.100.7.0
SM : -255.0.0.0

I'm a bit confused on your:
Q1. 4.4.0.0 with a mask of 255.0.0.0
Q2. 7.100.7.0 with a mask of 255.0.0.0

4.4.0.0 is a Class A address it has the default mask of 255.0.0.0.
That said normally when your learning you would use something like split 4.0.0.0 with a mask of 255.0.0.0 into 4 equal subnets

4.4.0.0/8 would actually be a ip address, not a subnet (network) address.
Our subnet id for this network would be 4.0.0.0 with a mask of 255.0.0.0

4.0.0.0 = the network/subnet ID (it is the first subnet but it is also our only subnet)
4.0.0.1 = the first use-able address
4.255.255.254 = last use-able address
4.255.255.255 = broadcast address

So your 4.4.0.0 throws me for a loop....

The same can be said for the 7.100.7.0 with a mask of 255.0.0.0

What would make more sense if the questions were:

Q1. Divide the following network address into 4 equal subnets

IP 4.4.0.0
SM 255.255.0.0

This question is asking for you to make four subnets equal in length. You need to find out the how many subnet bits to "borrow" (its 2 bits) By borrowing two subnet bits you will have a mask that has 4 subnets. The mask would be 255.255.192.0 for all 4 of these subnets.
subnet 1 = 4.4.0.0
subnet 2= 4.4.64.0
subnet 3 = 4.4.128.0
subnet 4 = 4.4.192.0

Q2. Divide the network into equal subnets such that each subnet can support 30 hosts.
IP = 7.100.7.0
SM = 255.255.255.0

Note: Even thou this is a class A address it doesn't mean that you can't be given a 7.100.7.0/24 address to work with.
we need to figure out how many host bits to borrow to get 30 host per subnet. (you need 5 bits)

5 bits gives you 32 but we subtract 2 for the subnet ID and the broadcast ID. We meet the requirement of needing 30 useable ip addresses per subnet. This leaves us 3 bits left over, so we will have 3bits to be used for the subnets. This gives us 8 subnets.

Our network mask will be 255.255.255.224
subnet 1 = 7.100.7.0
first ip: 7.100.7.1
last useable ip: 7.100.7.30
broadcast: 7.100.7.31

subnet 2= 7.100.7.32
subnet 3 = 7.100.7.64
subnet 4 = 7.100.7.96
subnet 5 = 7.100.7.128
subnet 6= 7.100.7.160
subnet 7 = 7.100.7.192
subnet 8 = 7.100.7.224

That all said; I think you should check out the link that Rob posted and/or read up on subnetting.
P.S. I like to use a subnet calculator to check my work