IP Addressing and Subnetting Exercise

Punjab University College of Information Technology, University of the Punjab.

IP Addressing and Subnetting Exercise

SUBMITTED BY: M. Adeel ROLL #: CCNA1005049 ----------------------------------------------------------------------------------------------------------1. Write the default subnet Masks for the Class A, Class B and Class C IP addresses. Ans: For class A: 255.0.0.0 For class B: 255.255.0.0 For class C: 255.255.255.0

2. How we can distinguish Class A, Class B, Class C, Class D and Class E IP addresses from each other. Write the range of first octet in binary and decimal for all the 5 IP address classes Ans: IP addresses have certain range according to their class in which they reside. For example:

Class Address A 1.0.0.0 B 128.0.0.0 C 192.0.0.0 D 224.0.0.0 E 240.0.0.0 www.syngress

Ending Address 127.255.255 255 191.255.255.255 233.255.255.255 239.255.255.255 255.255.255.255

3. Write the default subnet Masks for the following IP addresses: a. 100.100.225.100 b. 200.0.0.2 c. 190.47.115.0 d. 192.11.39.2 e. 101.7.80.0 Ans: a: 255.0.0.0 b: 255.255.255.0 c: 255.255.0.0 d: 255.255.255.0 e: 255.0.0.0

4. Write down the three available ranges for assigning Private IP addresses recommended by IANA

(Internet Assigned Number Authority). Ans: These are the available three ranges for assigning Private IP addresses recommended by IANA:

Address Blocks 10.0.0.0 – 10.255.255.255 172.16.0.0 – 172.31.255.255 192.168.0.0 – 192.168.255.255

5. What do we mean by Loopback address. Write down a Loopback address and its use.

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Punjab University College of Information Technology, University of the Punjab. Ans: The loopback interface is not a physical interface and has no hardware

associated with it. It is a software interface that is always reachable regardless of the physical interface status. RFC3513 defines the loopback interface address as 0:0:0:0:0:0:0:1, or ::1 in condensed form.An IPv6 node uses the loopback interface to send packets to itself.The standard prohibits a node from forwarding a packet with a destination address of a loopback.

6. What is the difference between a broadcast address and Network address? Why the all zeros and all ones addresses are usually not assigned as host IP addresses?

Ans: Network address This is the designation used in routing to send packets to a remote network— for example, 10.0.0.0, 172.16.0.0, and 192.168.10.0. Broadcast address The address used by applications and hosts to send information to all nodes on a network is called the broadcast address. Examples include 255.255.255.255, which is all networks, all nodes; 172.16.255.255, which is all subnets and hosts on network 172.16.0.0; and 10.255.255.255, which broadcasts to all subnets and hosts on network 10.0.0.0.

7. A mask is used to distinguish how many bits are there in Network ID portion and how many are in

host ID portion. We can extract the Network Address from the given IP address using the mask. (Assume that no subnetting is done). Extract the network address from the following IP addresses: a. 139.65.225.4 b. 201.35.20.18 c. 190.47.115.6 d. 192.11.39.2 e. 10.7.80.0 Ans: a: It belongs to class B(16-bit) so 2 portion is for network address and 2 portion is for hosted address. b: It belongs to class C(24-bit) so 3 portion is for network address and 1 portion is for hosted address. c: It belongs to class B(16-bit) so 2 portion is for network address and 2 portion is for hosted address. d: It belongs to class C(24-bit) so 3 portion is for network address and 1 portion is for hosted address. e: It belongs to class A(8-bit) so 1 portion is for network address and 3 portion is for hosted address.

8. A broadcast address is the one that addresses to all the hosts in any network. State that to create a broadcast address, all the bits of network ID portion, or all the bits of host ID portion are set to 1? Write down the broadcast addresses of the networks to which the following IP addresses belong. (No subnetting) a. 139.65.225.4 b. 201.35.20.18 c. 190.47.115.6 d. 192.11.39.2 e. 10.7.80.0 Note: First of all find network address of each address then find broadcast of that network. Ans:

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9. In subnetting, we actually borrow some bits of Host ID to be used as Subnet ID. Each Subnet ID

is used to identify a unique subnet and each host ID is used to identify a unique host within a subnet. If you add more bits to the subnet ID portion, then the hosts per subnet will increase or decrease? Ans: If we add more bits to the subnet ID portion, then the hosts per subnet will be decrease.

10. Subnet Mask or Custom mask tells us that how many bits are used for Subnet ID portion and how

many for host ID portion. Remember, that in a subnet mask, we place 1s against all network ID and subnet ID bits and 0s against all the host ID bits. Identify how many bits are used for subnetting in the following IP address using its subnet mask: a. IP Address: 139.65.225.4 Subnet Mask: 255.255.224.0 b. IP Address: 139.65.225.4 Subnet Mask: 255.255.248.0 c. IP Address: 201.35.20.18 Subnet Mask: 255.255.255.128 d. IP Address: 201.35.20.18 Subnet Mask: 255.255.255.240 e. IP Address: 190.47.115.6 Subnet Mask: 255.255.128.0 f. IP Address: 190.47.115.6 Subnet Mask: 255.255.252.0 g. IP Address: 192.11.39.2 Subnet Mask: 255.255.255.192 h. IP Address: 192.11.39.2 Subnet Mask: 255.255.255.224 i. IP Address: 10.7.80.0 Subnet Mask: 255.240.0.0 j. IP Address: 10.7.80.0 Subnet Mask: 255.255.128.0 Ans:

11. Extract the Network Addresses of the given IP addresses in question number 10, using the subnet

masks given with them. (Remember that ANDing the IP address with the Mask extracts the network address from the given IP address).

Ans:

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12. Specify a suitable Subnet Mask for the following cases: (You have to decided how many bits should be taken as subnet ID from the host ID portion to satisfy the required number of subnets). a. Class A Network with 10 subnets b. Class B Network with 120 subnets c. Class B Network with 13 subnets d. Class C Network with 20 subnets e. Class A Network with 1115 subnets f. Class A Network with 5000 subnets g. Class B Network with 500 subnets h. Class C Network with 21 subnets

Ans:

13. Suppose you have a class B Network 172.121.225.0. Your task is to design a subnet scheme so that we can create 130 Network segments (subnets) within this Network. a. How many bits would you use for the subnet ID? b. How many bits would you use for the Host ID? c. How many maximum possible subnets will be there? d. How many maximum possible hosts will be there in each subnet? e. Write down the Subnet Mask of your scheme. f. Write down the first valid IP address, last valid IP address and the broadcast address of the Third subnet of your scheme. Ans:

14. Suppose you have a class C Network 206.94.115.0. Your task is to design a subnet scheme so

that we can create 14 Network segments (subnets) within this Network. Each subnet should support 10-12 hosts. a. How many bits would you use for the subnet ID? b. How many bits would you use for the Host ID? c. How many maximum possible subnets will be there? d. How many maximum possible hosts will be there in each subnet? e. Write down the Subnet Mask of your scheme.

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f. Write down All the valid IP addresses, the broadcast address of the First subnet of your scheme.

Ans:

15. You joined an ISP and your first assignment to distribute the 160.16.0.0 /16 address among these blocks of customers as follows: a. The first group has 200 medium size businesses, each needs 128 addresses. b. The second group has 400 small businesses, each needs 16 addresses. c. The third group has 2048 households, each needs 4 addresses. Design the sub blocks and give the slash notation for each sub block. Find out how many addresses are still available after these allocations. Ans:

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