DNS port no: 53

DNS system uses fully qualified domain names [FQDN] to identify both the names of systems

and the network on which the system is located.

Forward lookup zone: It resolves hostname to IP on the internet

Reverse Lookup zone: it resolves IP to hostname on the internet.

What is DNS?

Ans : Domain Name Servers (DNS) are the Internet's equivalent of a phone book. They

maintain a directory of domain names and translate them to Internet Protocol (IP)

addresses. This is necessary because, although domain names are easy for people to

remember, computers or machines, access websites based on IP addresses

What is Active Directory? Ans: Active Directory is a central point for storing , Organizing, Managing and

Controlling Networks Objects Such as Users, Computers & Groups.

What is Organizational Units(OU)?

Ans: It is a logical container used to organize objects within a same domain. Objects such as

Users, groups, and other OU’s can be stored.

Network Topologies are of two types 1. Physical Topology(Ring, Bus) 2. Logical topology(Ring,

Bus, Mesh, Star, Hybrid)

Dhcp Port no: 67(Server) 68(client)

NTP port no: 123

TCP port No: 23

FTP port no 21

TFTP port no 69

ARP uses port 219

HTTP Port no 80

HTTPS port no 443

Internet Protocols work on layer 3 of the OSI model,

CIDR is used to represent a SUBNET mask and is repreented by notation “\”.

IP SUBNETTING is the process in whch large Network can be broken off into smaller Groups of

Subnetworks.

We use VLAN so that we can create smaller Broadcast Domain within a Layer 2 device

internetwork by assigning different ports in on the switch to different subnetwork

A trunk port is a port that is assigned to carry traffic for all the VLANs that are

accessible by a specific switch, a process known as trunking.

The Spanning Tree Protocol (STP) is an older network protocol that ensures a loop-

free topology for any bridged Ethernet local area network. The basic function of STP is

to prevent bridge loops and the broadcast radiation that results from them.

Spanning tree PortFast is a Cisco enhancement to STP used to allowports attached to

end devices to transition from a Blocked or Disabled state to the Forwarding state,

allowing devices to begin sending and receiving data immediately.

Network Address Translation (NAT) is a way to map an entire network (or networks) to a

single IP address. NAT is necessary when the number of IP addresses assigned to you

by your Internet Service Provider is less than the total number of computers that you

wish to provide Internet access for.

load balancing distributes workloads across multiple computing resources, such as

computers, a computer cluster, network links, central processing units or disk drives.

The Address Resolution Protocol (ARP) is a telecommunication protocol used for

resolution of network layer addresses into link layer addresses, a critical function in

multiple-access networks.

The Reverse Address Resolution Protocol (RARP) is an obsolete computer

networking protocol used by a client computer to request its Internet Protocol (IPv4)

address from a computer network, when all it has available is its Link Layer or hardware

address, such as a MAC address.

OSI model developed in late 1970s