CCNA – Subnetting Questions 4

To all and xallax

can you please help me with this..
What is the summarized for these network

172.1.4.0/25
172.1.4.128/25
172.1.5.0/24
172.1.6.0/24
172.1.7.0/24

my answer id 172.1.0.0/21 but in the dump it’s 172.1.0.0/22 please help me with this..thank you so much for your help..

@me
172.1.4.0/25
this is 172.1.4.0 ~ 172.1.4.127

172.1.4.128/25
this is .4.128 ~ . 4.255

172.1.5.0/24
.5.0 ~ .5.255

172.1.6.0/24
.6.0 ~ .6.255

172.1.7.0/24
.7.0 ~ .7.255

it is from .4.0 to .7.255
it fits perfectly in a block of 4.0
4.0 is 2 bits in the 3rd octet and 8 bits in the 3th octet, that’s 10 bits per total, that leaves 22 bits for the subnet (/22 in CIDR notation)

let’s put it this way. you have to figure out the subnet mask for a subnet that starts at .4.0 and ends at .7.255
the subnet mask for it is 255.255.252.0
how many bits? 22

Hi Xallax,

Thank you so much for your explanation..i got it :) Thanks again :)

Q8 is still confusing after reading all of these answers and explanations.

And moncho was using ClassB subnets, these are Class A, not B!

Subnets Hosts Total
A. 10.10.0.0/18 = 1,024 16,382 = 17,406
B. 10.10.0.0/25 = 131,072 126 = 131,198
C. 10.10.0.0/24 = 65,536 254 = 65,790
D. 10.10.0.0/23 = 32,768 510 = 33,278
E. 10.10.0.0/16 = 256 65,534 = 65,790

If you want the least amount of Host & Subnets, then A would be your best bet, but all of these are terrible answers.

Please someone let me know what I am missing here.

NOTE: 113 point-to-point links, thus this means subnet addresses, Not Hosts.

/15 = 128 131,070 = 131,198
/16 = 256 65,534 = 65,790
/17 = 512 32,766 = 33,278
/18 = 1,024 16,382 = 17,406

I thought /15 -/17 would be better but /18 appears to be the best one. It wastes the least amount of Host & Subnets.

/20 would be the best (4096 + 4094 = 8190)

Please someone point out what I am doing wrong. I think I am correct here.

Yo 9tut gret stuff you layed here man…send latest brain dumps~ dougenius@live.com

I passed my ccna exam today Praise be to God! Thank you Jesus! and thanks to 9TUT for the tutorials and explanations, great site and thanks to xallax for your explanations to questions and thanks to http://www.examcollection.com for the dumps. Pls guys lets donate and help to keep this site up!

48 ques for exams including 3 simulation, I had EIGRP, Acesslist2 and VTP. Make sure the practice the simulation, use packet tracer or gns3. Best wishes to all!

For Q8 I put answer D, but when I was working it out I made the mistake of counting the subnets as if it was a class B address.

As it is class A then Kurt is right that the amount of subnets will be these huge figures given so the question could be flawed.

Is it that you are discarding the first two octets because 10.10.0.0 appears to be the network ID you are starting with so you mask out the first two octets and count from there 2, 4, 8, 16, 32, 64, 128 which fits in 113 subnets therefore it is /23. You would then have network IDs of 10.10.0.0, 10.10.2.0, 10.10.4.0, 10.10.6.0, etc. ?

Q8,

I found out how it is answer D. What you have to do is look at the subnet mask and which is /30 and then to find the difference between each of the networks which gives you:

A – 12
B – 5
C – 6
D – 7
E – 14

So you then work out how many of subnets for this number of bits, 7 bits gives you 128 which is the best fit for the requirement in the question of 113 networks, with 2 hosts each (point-to-point). Hope this makes more sense now.

Hello all,

I got a prob with que no 2. Please brief me how we move 2 bits to left from 24 to 22?

Thanks

hello,
i got a problem with Q4. i want to know how option B is the correct answer when option D is also with /26 ?

hi sumit..

if you calculate the range or block size it will come out to be 64 and there will be 4 subnets in this case. well first subnet is 192.168.1.0 and second is 192.168.1.64
first three networks in the diagram are from first range so it has to be from 192.168.1.64/26

hope u got it.

this subnetting is really confusing becuz everyone does it their way……….hmmmmmm i am writing my test at the end of this month ……any good help regarding subnetting ,vlsm and summarization questions ???????????i wanna get them done easily …wts the best way /// plz help

@youngj: Please read my Subnetting tutorial: http://www.9tut.com/subnetting-tutorial

The Network 172.25.0.0 has been divided into 8 equal subnets. Which of the following IP address can be assigned to the hosts in the 3rd subnet if the IP subnet-zero command is configured on the router? Choose 3 correct answers.

1. 172.25.78.243

2. 172.25.98.16

3. 172.25.72.0

4. 172.25.94.255

5. 172.25.96.17

6 172.25.100.16

correct ans according to dump is

1 3 and 4.

9TUT could anyone explain how this is calculated?

regards,
Rutz

If they given the mask /27 then the subnet 0,32,64,96————-so on.The 3rd subnet is 64 and ip add. range between 64 to 95. That by the correct ans is 1 3 and 4. thanks

I find Wendell Odom’s product to be more inivttiue and easier to just jump right in. In my opinion, the design process that goes into designing any network simulation software, is similar to designing a game. Some games require you to learn the controls, before you can really get started, while others are so well thought out that you can well, just jump right in. However, if anyone has any plans to progress beyond the CCNA (eg. CCNP, etc.), I would recommend taking a look at the other two simulators. When I first purchased RouterSim’s Network Visualizer, it was still a buggy product and prone to crashes. Even so, it was the only worthwhile game in town, at the time (2004). I never got the opportunity to finish the labs, as I was called to active duty and served over seas for almost two years. RouterSim’s Network Visualizer has a particularly strict software license. You only get one, and in order to install it on another machine, you have to send your activation key back to the company (online, via the software itself). Once the license is back with the company, you can then install the software again on another computer, and then activate the product by downloading activation key from them once again. Ever served in the military? Well when you get those orders, you go. There is not a lot of time. You may have a few days to settle any pending business, like saying goodbye to your family and friends, making sure your will is in order, arrange for your bills to be paid, and so on. So transferring a software license wasn’t on the top of my list. My software was originally installed on a desktop and I was not about to lug that (and the monitor) with me in my ruck. By the time I came back, the CCNA exam had changed so much that my simulator was, yes outdated. I tried explaining my situation to the nice folks at RouterSim, but I was informed nicely that I can just purchase the upgrade. Remembering my experiences with the software crashes, I declined and signed up to take a CCNA cram class instead. Big mistake. For a newbie, cram courses don’t work. Eight days (8 hours a day) of instruction will not teach you the operations of a network and how Routers and Switches come into play so much so that you can pass the CCNA. Much less, get you so familiar with the input commands that you can use on the job. In my class, I had an Egyptian instructor who may be very knowledgeable, but help me if I can understand a darn thing that he was saying. I just couldn’t get pass the accent. The school did however, introduced me to Boson’s NetSim, a far superior product than my older version of RouterSim’s Network Visualizer. Oh yes, if you decide on taking a class, make sure that they give you access to ACTUAL Cisco equipment! They didn’t technically lie to me however, the school did have Cisco equipment, but that was a very brief show and tell. We primarily were working with the NetSim software. There are several versions now CCENT, CCNA, CCNP, etc. They also sell videos and mp3 s, besides the simulation software. Cisco seems to be endorsing them, you can find links to Boson from the Cisco website. To briefly describe the product, you basically have a network simulation software package along with a couple of pdf lab manuals (they are compressed and will appear once you’ve installed the software). I would print out the manuals and follow through the lessons, chapter by chapter. So why do I prefer Wendell Odom’s Network Simulator over the others? One, you get 4 licenses. Yes, you can install your product on FOUR separate computers. Two, the price. Wendell Odom’s Network Simulator is under $100 (Amazon price, retail is $149). RouterSim’s CCNA Network Visualizer is $229.00. And Boson’s NetSim for CCNA is $249. And third, the pdf step-by-step lessons on Wendell Odom’s Network Simulator pops up as you activate the corresponding lesson simulation. Something that I can really appreciate, as I will be traveling a lot on my new job, and don’t want to carry a hard copy lesson book with me, nor scroll through the pages to the lesson I want. Dual monitors would serve you well here. It really is just simpler to use. You are presented with a lesson menu on the right side. A diagram of your network is on the top left, and the command line section (where you type) is below that. Click on the computer icon on your virtual network, and on the command line section you’re looking at the CLI interpretation of what you would see if you were logged on to that computer. The same goes for the switches and the routers. Neat. Do bear in mind however, that network simulators are

@ Anonymous

The Network 172.25.0.0 has been divided into 8 equal subnets. Which of the following IP address can be assigned to the hosts in the 3rd subnet if the IP subnet-zero command is configured on the router? Choose 3 correct answers.
1. 172.25.78.243
2. 172.25.98.16
3. 172.25.72.0
4. 172.25.94.255
5. 172.25.96.17
6 172.25.100.16
correct ans according to dump is
1 3 and 4.

If you have 8 equal subnets you are looking at 32 hosts per subnet. Your subnets would be:

172.25.0.x
172.25.32.x
172.25.64.x
172.25.96.x

This question is specifically looking for hosts in the 3rd subnet. So we would be interested in:

172.25.64.1 – 172.25.64.95.254

Therefore, the correct answers given the choices are 1, 3 and 4

hi, could someone please simplify Q3 for me please?

than u very much

Can anyone mail me dumps please? atman.trivedi@hotmail.com Many thanks

no dumps needed on subetting..either u know it or not….907!!..thx 9tut!!

You have been asked to come up with a subnet mask that will allow all three web seivers to be on the same network while proving the maximum number of subnets. Which network address and subnet mask meet this requirement?

A.
192.168.252.8 255.255.255.252

B.
192.168.252.16 255.255.255.252

C.
192.168.252.8 255.255.255.248

D.
192.168.252.0 255.255.255.252

E.
192.168.252.16 255.255.255.240
——————————————–

Why the answer is C..?
Can anyone explain please..?

@malikccna
the smallest subnet to fit 3 servers is the one from option C

@9tut Please check for typo – Right Menu URLs showing the same Questions content
http://www.9tut.com/ccna-subnetting-questions-3
http://www.9tut.com/ccna-subnetting-questions-4

What is the summarized for these network
172.1.4.0/25
172.1.4.128/25
172.1.5.0/24
172.1.6.0/24
172.1.7.0/24

my answer id 172.1.0.0/21 but in the dump it’s 172.1.0.0/22

@ me and xallax meaning the rite ans is 172.1.4.0/22 not 172.1.0.0/22 as in the dump.
@ me check from ur dump if 172.1.4.0 is part of the ans????

can somebody help me with this question please? http://www.aiotestking.com/cisco/2012/04/which-three-statements-correctly-describe-network-device-a/

@Q8

Hi All!

This almost wated a lot of time on this so just sharing what I have learnt if this helps!

when we do according to the basics we know we have for 113 links we need is

2*2*2*2*2*2*2=7 bits to be reserved so

we have is some class address where 7 bits have to be reserved.

from the given options below we see them like this

10.10.0.0/23 subnetted with mask 255.255.255.252

so for 255.255.255.252 is nothing but /30 so if we

by increasing given /23 to /30 we have increased address by 30-23=7

which can give 2^7 addresses we need.

say if we take other options we have

10.10.0.0/25 subnetted with mask 255.255.255.252

/25 to /30 we have 30-25=5

2^5=32

but we need 113
Hope this helps

Thanks

@kai

Which three statements correctly describe Network Device A? (Choose three.)

Here the main Idea is

If they are on the same subnet we need not give the IP address. If they are not then we have to give them

Given two address are 10.1.0.36 and 10.1.1.70

So if we take

A.
With a network wide mask of 255.255.255.128, each interface does not require an IP address.

we can see that if we use this mask they are on different subnet so we need ip, so A is incorrect.
B.
With a network wide mask of 255.255.255.128, each interface does require an IP address on a unique IP subnet.
This is correct as we do require IP addresses

C.
With a network wide mask of 255.255.255.0, must be a Layer 2 device for the PCs to communicate with each other.

NO, we need layer 3 as IP address is involved.

D.
With a network wide mask of 255.255.255.0, must be a Layer 3 device for the PCs to communicate with each other.
YES.
E.
With a network wide mask of 255.255.254.0, each interface does not require an IP address.
Yes, as both are on the same subnet

Thanks

Hi, Please can some one explained Question no. 3

Hallo

Plz can someone explain to me why on question 4 answer B is right? and why not D.

thanks

In the ACL examples there is one that says
“permit host B from accessing the finance server..”
“deny host B from accessing the OTHER server not the whole network”

Shouldn’t the first request above say DENY host B from accessing the finance server?
Usually you deny something FROM and permit something TO.
Besides that … permitting it to the server useless as the other hosts also have permission
from the third statement.

the third statement is “acces-list 100 permit ip any any”

hi
ref Q1
Each subnet has 30 hosts /27
should this not be 6 bits? i thought that 30 hosts would = 30+2 (32) which would be 6 bits
any help?

Can somebody plz explain this question…

The network administrator is asked to configure 113 point-to-point links. Which IP addressing scheme best defines the address range and subnet mask that meet the requirement and waste the fewest subnet and host addresses

A. 10.10.0.018 subnetted with mask 255.255.255.252
B. 10.10.0.025 subnetted with mask 255.255.255.252
C. 10.10.0.024 subnetted with mask 255.255.255.252
D. 10.10.0.023 subnetted with mask 255.255.255.252
E. 10.10.0.016 subnetted with mask 255.255.255.252

i dont get why B is correct, E makes more sense to me since you are subnetting from a Class A address.

Can somebody plz explain this question…

The network administrator is asked to configure 113 point-to-point links. Which IP addressing scheme best defines the address range and subnet mask that meet the requirement and waste the fewest subnet and host addresses

A. 10.10.0.0/18 subnetted with mask 255.255.255.252
B. 10.10.0.0/25 subnetted with mask 255.255.255.252
C. 10.10.0.0/24 subnetted with mask 255.255.255.252
D. 10.10.0.0/23 subnetted with mask 255.255.255.252
E. 10.10.0.0/16 subnetted with mask 255.255.255.252

i dont get why B is correct, E makes more sense to me since you are subnetting from a Class A address.

“i dont get why B is correct, E makes more sense to me since you are subnetting from a Class A address.”

It’s not the correct answer is D

Look at it this way:
A. 10.10.0.0/18 – Useable range 10.10.192.0 – 10.10.255.255 (around 7936 ip addresses) subnetted with /30 (1984 blocks of 4 addresses)

B. 10.10.0.0/25 – Useable range 10.10.0.128 – 10.10.0.255 (128 addresses) subnetted with /30 (32 blocks of 4 addresses)

B. 10.10.0.0/24 – Useable range 10.10.0.0 – 10.10.0.255 (256 addresses) subnetted with /30 (64 blocks of 4 addresses)

D. 10.10.0.0/23 – Useable range 10.10.0.0 – 10.10.1.255 (around 512 ip addresses) subnetted with /30 (128 blocks of 4 addresses)

E. 10.10.0.0/16 – Useable range 10.10.0.0 – 10.10.255.255 (65,280 ip addresses) subnetted with /30 (16,230 blocks of 4 addresses)

Since you only have a requirement of 113 WAN Links of four addresses each (network, host, host, broadcast)….some under fill the requirements and some are overkill.

TY 9tut.

Today I have passed the CCNA. (860/825)
50 questions 3 labs (VTP, EIGRP, ACL). 35 from 9tut.

Also thanks a lot Brar and Sekhar (still valid from examcollection)

Ty again 9tut

from here none

please help me..why we should give same set of network ip address to serial link
this is my email tamilarasiek@gmail.com

MalikCCNA
three web server need to have three valid ip address on the same sabnet or the last three bits in last octet
00000000.00000000.00000000.00000/000 for that the mask will be
11111111.11111111.11111111.11111 000 or 255.255.255.248

Guys help me with an activation code for visual certexam manager.i cant access vce files.Even the trial version seems fake.

@9tut: do we have a route summarization topic here? thanks

Valid Que :D

Q:7

Passed CCNA, question 8 from here.

ques 8 was in the exam today

Q-4
Why not Option-D…???

Q-4..!!
Sorry i got it, they are asking “which subnet”, 56 isn’t the subnet so the only option left is 64

Q8..!!
Answer should be B (/25) Coz 7 bit will be off then and 2^7=128>113

Please Explain