CCNA – Subnetting Questions 2
Here you will find answers to Subnetting Questions – Part 2
Question 1
Refer to the exhibit. Which VLSM mask will allow for the appropriate number of host addresses for Network A?
A. /25
B. /26
C. /27
D. /28
Answer: A
Explanation
We need 66 hosts < 128 = 27 -> We need 7 bits 0 -> The subnet mask should be 1111 1111.1111 1111.1111 1111.1000 0000 -> /25
Question 2
Refer to the exhibit. Which subnet mask will place all hosts on Network B in the same subnet with the least amount of wasted addresses?
A. 255.255.255.0
B. 255.255.254.0
C. 255.255.252.0
D. 255.255.248.0
Answer: B
Explanation
310 hosts < 512 = 29 -> We need a subnet mask of 9 bits 0 -> 1111 1111.1111 1111.1111 1110.0000 0000 -> 255.255.254.0
Question 3
Refer to the exhibit. Which mask is correct to use for the WAN link between the routers that will provide connectivity while wasting the least amount of addresses?
A. /23
B. /24
C. /25
D. /30
Answer: D
Explanation
For WAN link we only need 2 usable host addresses for 2 interfaces on the routers. The subnet mask of /30 gives us 22 – 2 = 2 usable host addresses. Also remember that “/30″ is famous for point-to-point connection because it wastes the least amount of addresses.
Question 4
Refer to the exhibit. What is the most appropriate summarization for these routes?
A. 10.0.0.0/21
B. 10.0.0.0/22
C. 10.0.0.0/23
D. 10.0.0.0/24
Answer: B
Explanation
We need to summarize 4 subnets so we have to move left 2 bits (22 = 4). In this question we can guess the initial subnet mask is /24 because 10.0.0.0, 10.0.1.0, 10.0.2.0, 10.0.3.0 belong to different networks. So “/24″ moves left 2 bits -> /22.
Question 5
On the network 131.1.123.0/27, what is the last IP address that can be assigned to a host?
A. 131.1.123.30
B. 131.1.123.31
C. 131.1.123.32
D. 131.1.123.33
Answer: A
Explanation
Increment: 32
Network address: 131.1.123.0 & 131.1.123.32
Broadcast address: 131.1.123.31
Both 131.1.123.30 & 131.1.123.33 can be assigned to host but the question asks about the “last IP address” so A is the correct answer.
Question 6
The ip subnet zero command is not configured on a router. What would be the IP address of Ethernet0/0 using the first available address from the sixth subnet of the network 192.168.8.0/29?
A. 192.168.8.25
B. 192.168.8.41
C. 192.168.8.49
D. 192.168.8.113
Answer: C
Explanation
The “ip subnet zero” is not configured so the first subnet will start at 192.168.8.8 (ignoring 192.168.8.0).
Increment: 8
1st subnet: 192.168.8.8
2nd subnet: 192.168.8.16
3rd subnet: 192.168.8.24
4th subnet: 192.168.8.32
5th subnet: 192.168.8.40
6th subnet: 192.168.8.48 -> The first usable IP address of 6th subnet is 192.168.8.49
Question 7
For the network 192.0.2.0/23, which option is a valid IP address that can be assigned to a host?
A. 192.0.2.0
B. 192.0.2.255
C. 192.0.3.255
D. 192.0.4.0
Answer: B
Explanation
Increment: 2
Network address: 192.0.2.0, 192.0.4.0
Broadcast address: 192.0.3.255
-> 192.0.2.255 is not a broadcast address, it is an usable IP address.
Question 8
How many addresses for hosts will the network 124.12.4.0/22 provide?
A. 510
B. 1022
C. 1024
D. 2048
Answer: B
Explanation
/22 gives us 10 bits 0 -> 210 – 2 = 1022. Notice that the formula to calculate the number of host is: 2k – 2.
Question 9
The network default gateway applying to a host by DHCP is 192.168.5.33/28. Which option is the valid IP address of this host?
A. 192.168.5.55
B. 192.168.5.47
C. 192.168.5.40
D. 192.168.5.32
E. 192.168.5.14
Answer: C
Question 10
Which two addresses can be assigned to a host with a subnet mask of 255.255.254.0? (Choose two)
A. 113.10.4.0
B. 186.54.3.0
C. 175.33.3.255
D. 26.35.2.255
E. 17.35.36.0
Answer: B D
Hello guys,
Please explain me how to choose the default gateaway..is there any criteria..??
Not sure what you mean. The DG is normally an IP address within the same subnet as the host but applied on a different device. I normally give the switch VLAN the first IP address and the DG (router) the last, this will allow clients on the subnet to have consecutive IP addresses. Depends totally on your network layout.
You mean to say if suppose anyip address is given 192.168.93.97 255.255.255.240…..then i should choose default gateaway ( router) be 192.168.93.110….in case of switch vlan be 192.168.93.97……Is that right..???
The value of Default gateaway can be anything within the same network…????
q. 8 in exam
About q 6
The ip subnet zero is a default setting in Cisco IOS, according to Wendell Odom’s books. So I think that the correct answer is B.
640-802 exam book next tuesday scared lol been studying hard for this hope i am rewarded any advice would be nice.
thomasbulloch1988@gmail.com
@thomas, please would you brief me a bit after your exams then, on how the exam is, since I will be writing too on friday that same week, wishing you best of luck… immyrichardson@yahoo.com
Please answer my questions anyone…!!! Waiting for your reply…!!!
yes except not the last address or broadcast address
Thanks 9tut. I made it. I passed my CCNA 200-120 today. The sim is Access-list 1 , Access-list 2 & EIGRP. A lot of new questions like Netflow, Syslog, SNMP, VRRP, and GLBP.
Isn’t stil actual 640-802?
it is bra matt damon
Can any one explain Q10
Can anybody explain how to calculate correctly
Question 10
Which two addresses can be assigned to a host with a subnet mask of 255.255.254.0? (Choose two)
A. 113.10.4.0
B. 186.54.3.0
C. 175.33.3.255
D. 26.35.2.255
E. 17.35.36.0
Answer: B D
Abs619
From the Subnet mask 255.255.254.0, you care about the third octet (254) convert that to binary 11111110
From that you know that the increment is 2. ( 128 64 32 16 8 4 {2} 1). Remember, all you care about are the last two octets, so the increment will be X.X.2.0 – X.X.4.0 – X.X.6.0 and the last IP address cannot be assigned as it is reserved for Broadcast, so the only assignable IP addresses within the 2.0 and 4.0 are 3.0 and 2.255 as the broadcast will be 3.255.
any thing important for some of us who preparin g to tape the exam
@Anas Salo
Could you please specify why your answers are correct on Q10 please? Thank you.
kb8…… Thanks a lot buddy… Now I understand :-)
Cheers :-)
Can any bdy plz explain Q9, how c is the answer
this is address 192.168.5.33 /28
but the subnetmask is /28 = 255.255.255.240
the hop is 0-16-32-48-64……
the address ip for the dhcp is 192.168.5.33.
ip valid 192.168.5.33 to 192.168.5.47
I had passed my exam 841/1000 i’m so very happy end satisfaction, thanks guys
i done ACL’S, EIGRP, VTP lab, were same that the Lam here.
thanks a lot
I passed my CCNA 200-120 yesterday with score 1000/1000.
The sim is Access-list 1 , Access-list 2 & EIGRP.
Thanks 9tut. I made it.
@xallax
You have been asked to come up with a subnet mask that will allow all three web servers 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
in this questions why they choose answer C not A or D can you clearfy it?
248 sobran 3 bits para hosts
For question 7, how can class c address 192.0.2.0 use /23 subnet mask? Class c can use only from /24 onwards. Pls clarify.