Basic NETWORKING interview quotations

Basic NETWORKING interview quotations

1. What is MAC address

The address for a device as it is identified at the Media Access Control (MAC) layer in the network architecture. MAC

address is usually stored in ROM on the network

adapter card and is unique.

                      

2. What is subnet

A generic term for section of a large networks usually separated by a bridge or router.

3. What is Brouter

Hybrid devices that combine the features of both bridges and routers.

4. How Gateway is different from Routers

A gateway operates at the upper levels of the OSI model and translates information between two completely different

network architectures or data formats.

5. What are the different type of networking / internetworking devices

Repeater:

Also called a regenerator, it is an electronic device that operates only at physical layer. It receives the signal in the

network before it becomes weak, regenerates the original

bit pattern and puts the refreshed copy back in to the link.

Bridges:

These operate both in the physical and data link layers of LANs of same type. They divide a larger network in to smaller

segments. They contain logic that allow them to

keep the traffic for each segment separate and thus are repeaters that relay a frame only the side of the segment

containing the intended recipent and control congestion.

Routers:

They relay packets among multiple interconnected networks (i.e. LANs of different type). They operate in the physical,

data link and network layers. They contain software

that enable them to determine which of the several possible paths is the best for a particular transmission.

Gateways:

They relay packets among networks that have different protocols (e.g. between a LAN and a WAN). They accept a

packet formatted for one protocol and convert it to a

packet formatted for another protocol before forwarding it. They operate in all seven layers of the OSI model.

 What are the important topologies for networks

BUS topology:

In this each computer is directly connected to primary network cable in a single line.

Advantages:

Inexpensive, easy to install, simple to understand, easy to extend.

STAR topology:

In this all computers are connected using a central hub.

Can be inexpensive, easy to install and reconfigure and easy to trouble shoot physical problems.

RING topology:

In this all computers are connected in loop.

Advantages:

All computers have equal access to network media, installation can be simple, and signal does not degrade as much as

in other topologies because each computer

regenerates it.

What is point-to-point protocol

A communications protocol used to connect computers to remote networking services including Internet service

providers.

5. Ip Address Ranges:
Class A: 0-126. 127 is a Broadcast
Class B: 128-191
Class C: 192-223
Class D: 224-239
Class E: 240-255.

what is a Firewall:
Firewalls are of two types:
-Hardware Firewall
-Software Firewall.
Firewall in simple manner is bascially the utility to provide the security over the network. These are the security measures that prevents the network’s in and out traffic to pass through the specific Security filters so that the unwanted and unsecure data can be stopped from entering into the network..
further… as a security measure it also depends on the network designer and implementer that how to use a Firewall mean to say the security measures like how to present the content filtering and Url filtering which type of firewall should be used and where to put it..

first of all one should know what a protocol actually means:
A Protocol is bascially set of rules designed and developed for the internetwork or can say intranetwork Communications How does a DHCP work ? When a pc with no Ip address just with an MAC addrress boots up , what are the steps that Happen till the time a Ip is given to the pc from a DHCP.

how to change MAC Address.?

you can change a mac address easly. go to the desktop>write click on the my computer icon>properties>device manager>Network Adapters> properties> advance>network address.. and then chnage the value. The value should be hexadecimal or 16 octat

Telnet   --                                                                                                 A application layer process of connection remote compter and local Area Network compter by specifing the ip address by a specific port,

Firewall                                                                                                   The rules which are used for Passing traffic thats is packets in network layer and frame is datalink layer on a specific port it can be two type
1.Hardware
2.Software

 TCP -                                                                                                        A transport layer protocol sued for reliable delivery of segmented packets
IP is network layer protocol used for end to end delivery of two nodes not reliable.

 How ISA Server Works ?

ICS(Internet Connection Sharing)
In this method you can just enable Internet Connection Sharing check on your gateway.. The limitation of ICS is you must have 192.168.X.X IP addressing scheme on your network. another limitation of ICS is it can support upto 15 Computer(approx.. dont remember exact figure).

What are some of the problems associated with operating a switched LAN?
A switched LAN (Local Area Network) may use a Gigabit Ethernet switch that includes different ports connected to PCs and to layer 3 routers. The routers connected to different switch ports can not immediately identify failures either of other routers or of the ports and links by which they are connected to the switch. The routers currently have to rely on slow timeout mechanisms, such as missed hello packets, to detect failures on other links connected to the switch.
Thus, the time required to detect failures can and often does dominate the time required for a routing algorithm to determine a new network topology around a detected failure (convergence time).

Ø  What are the well known ports?

     Netstat - 15

FTP – 20 (data) and 21(Control)

SSH -22

Telnet – 23

SMTP -25

Wins - 42

DNS -53

DHCP – server 67 & clint  68

TFTP – 69

HTTP – 80 Secure 81

Kerbros - 88 *

POP3 – 110

NNTP -         119

Net bios - 139

SNMP - 161

IMAP3 – 220

LDAP - 389

SSL - Secuer socket leyar - 443

RIP - 520

MS Sql - 1433

NFS - 2049

RDP - Remote Desk top Protocals - 3389

connection a LAN, the question is..how does it identify, which computer it needs to send the packet to. For this it uses the concept of ARP, Address Resolution Protocol, which it uses over time to build up a table mapping from the Logical addresses to the Physical addresses. Each computer is identified using its MAC/Physical address ( u can use the ipconfig -all option to get ur MAC address).

VPN(Virtual Private Network )… these are bascially the logical networks on the physical line… you can have many VPN oveer same line..
Need of VPN arises when your company need to increase the network but don’t want to buy any more switches.. take an eg. your dept. your room is packed with employees and ur company need to add 4 more persons to ur deptt. what will they do.. the solution is to create VPN’s…you can configure the switch ports in other deptts. and create a specific VLAN of ur deptt.so that the persons can sit there and access to the required pcs.

 What are Pvt. IP address ?

Pvt. IP are IPs which are not used in Internet or which are not routable in

Internet. They are also called as non-routable IP's.
What is Subnet Mask ?                                                                               

Subnet  mask is used to differentiate Network ID and Host ID from a given IP

address. The default subnet mask are as under

 What is Loopback address ?

 The loopback address is 127.0.0.1. This address is used to check local TCP/IP

suite or local machine.

What portocol is used by PING ?

 Ping uses ICMP(Internet Control Management Protocol)

 What is used of Tracert ?

Answer : Tracert is a to find path information between source and desitnation. It show no.of hops between source and desitination. Tracert also uses ICMP protocol.

 What is full form of PING ?

Packet Internet Network Gopher

what is bandwidth of of CAT5 cable

 100 Mbps

What is the recommanded CAT5 cable length between switch and PC ?     100 meters

Similar device = cross cable

eg. switch to switch

PC to PC

Hub to HUB

Switch to HUB

PC to router

router to router

Unsimilar device = straight cable

eg. PC to switch

PC to HUB  and Router to Switch

Difference between domain and workgroup

Domain Workgroup

a. centralized network model decentralized network

b. Domain is controlled by DC No centrailzed control

c. Centralised login Local login

d. centrailsed user database local user databased

e. Easy and centrailsed management NA                                                             f. good for large network good for small network

 What is Web Server ?

 Web server is a server or application server which host or stores websites.

Every web site should have a name like www.vision.com and IP address. Eg. IIS, Apache server, etc.

 What is mail server ?

 Mail server is a software which maintains user mailboxes. eg : Exchange server

, Lotus domino, etc.

3) What is mail client ?

    A sofware used by client to access to mails stores on mail server. using mail

client software you can send mail and receive mail. Eg : Microsoft Outlook, Outlook

Express, Lotus notes, etc.

What is Proxy server ?

It is a softwar used for sharing of internet connection. Eg. Wingate, Winproxy,

Analog proxy, etc.

Port numbers for various application and services

There are total 65536 ports available. Below are the list of some well-known ports