Solution

Domain name system convert a given name to its IP address via DNS server by using DNS lookup or host.

Solution

TCP and UDP have a common field of only length and checksum.

Solution

Layer 4 firewall contains the physical layer, DLL, NL and TL. Therefore it can filter both Hosts as well as particular services on the host. For example, With port number 21 and an IP address of Host can block the FTP packet from that host.

Solution

1. TRUE - In Static Routing, it is set up manually and requires administration, and In Dynamic Routing, everything is done by routers Automatically.
2. TRUE - Static Routing works when traffic predictable & network is simple and Dynamic Routing calculates routes based on received updated network state information.
3. FALSE - Static Routing does not change based on network traffic and topology, But Dynamic Routing does change depending on network traffic and topology.
4. FALSE - LSR and DVR both are Dynamic routing algorithm

Solution

The main issue with Distance Vector Routing (DVR) protocols is Routing Loops. This routing loop in the DVR network causes Count to Infinity Problem. Routing loops usually occur when an interface goes down, or two-routers send updates at the same time.

Solution

When a packet is passed to the data link layer from the network layer IP address of the sender, the MAC address of the sender and the gateway of the network is attached. The MAC address of the sender is known to the sender but not the MAC address of the gateway. So ARP (Address Resolution Protocol) request is generated with the IP address of the gateway and is broadcasted, everyone except the gateway discards it, and gateway sends its MAC address.

Solution

Method 1

D-H key is g^(AB) mod n = 7^(3 x 6) mod 23= 18

Method 2,

Given n = 23 and g = 7.

Alice calculates 7^3 (mod 23), which is 21 and sends that to Bob.

Bob calculates 7^6 (mod 23), which is 4 and sends that to Alice.

(Note: 3 and 6 are secret to Alice and Bob, respectively, but both 21 and 4 are known by all.)

Alice receives 4 and calculates 4^3 (mod 23), which is 18, the secret key.

Bob receives 6 and calculates 21^6 (mod 23), which is 18, the same secret key.

Solution

TRUE - In the Routing method, Routing Table is the disadvantage in comparison to the flooding method.

TRUE - In the Routing method, Reliability is less, and in flooding method Reliability is high.

TRUE - In the Routing method, There is no duplicate packet, but in the flooding method, there are duplicate packets.

TRUE - In the Routing method, Traffic is low, but in the flooding method, traffic is high.

Solution

Solution

Confidential information should not be leaked to a third party. Confidential information must be encrypted before sending. A digital signature does not encrypt the message before sending.

Solution

IPV6 supports multicasting, anycast and unicasting, but it does not support broadcasting.

Solution

DNS - Port# 53

POP3 - Port# 110

FTP(Data) - Port# 20

FTP(Control) - Port# 21

Solution

True - If an application requires speed rather than reliability, then UDP is the best protocol. Eg. Multimedia application.

If an application needs one request & one reply kind of communication. Then connection establishment is not required; UDP is a better protocol. For example DNS, BootP, DHCP

Solution

True - Count-to-infinity is a problem only with DVR, not in LSR.

False - In LSR, the shortest path algorithm is run only at one node.

False - In DVR, the shortest path algorithm, runs only at one node.

True - DVR requires fewer messages than LSR.

Solution

N = p x q = 3 x 11 = 33,

n = (p - 1)(q - 1) = 2 x 10 = 20 => fi(n)

d = e^-1 mod n

=> e x d = 1 mod n

=> 3 x 7 = 1 mod 20 = > d = 7

Cipher value M’ = M^e mod N = 8^3 mod 33 = 17

Message M = M’^d mod N =17^7 mod 33 = 8