Difference between Internet and WWW....

Hi guys ,
The questions I m posting here are not really new but the problem is the answers to them vary subtly in different books and from people to people from whom I seek answers .

So I thought this might be the right place to get quenched.
Here are the Questions :

1. Difference between Internet and WWW
2. Difference between Virus , Worm and Trojan
3. Difference between internet (with small 'i') and intranet.

Please explain clearly and only if you are dead sure of them because I am already confused as answers vary a little every time I ask it from some one or search it on different sites.

Excuse me if I sound Dumb.

Wikipedia ?

M

1. You should start with wikipedia then discuss if something specific is doubtful.
2. Again what's wrong with wikipedia? And there was an article in howstuffworks.com, if I remember right. Check there.
3. Google should give you a lot on this. From what I know, internet > intranet and intranet is not accessible to everyone as Internet is. Maybe you should read the wikipedia entries of both the terms

I have referred Wikipedia also. Ok , let me directly put my doubts here.
1. Can we use anything on the Internet without using the WWW? If u say email , U still open ur browser and goto home page of say Yahoo and if u r using a website , u r using web , isnt it ?
2. If make a LAN in a lab , can it be called an intranet ????

I am asking these because such are often asked in our vivas and whatever we say the external says we are wrong and we cant ask him how because he is KING that time.

M

*www.webopedia.com/DidYouKnow/Internet/2002/Web_vs_Internet.asp

^^I have read that before also . The question still remains...
Can we use anything on the Internet without using the WWW? If u say email , U still open ur browser and goto home page of say Yahoo and if u r using a website , u r using web , isnt it ?

M

torrents, ftp.
As to emails not necessarily. We have mail clients which fetch mails from the mail server.

but mails , torrents files , ftp files are present in databases which are also considered a part of www , isnt it ?? Beacause i read it in one of my text books that " WWW is the collection of all the websites on the internet and if any information is to be made accessible to all the users , it has to be on the WWW."

can we see on the internet without www ..... no
can we see something on a server without www .... yes .... thts how u answer to those jack a$$ externals ...

M

no they aren't. www is something that is accessible over http. But these services use different protocols but they are made available over http.
From what I understand, in case of emails your browser connects to the site over http but the site connects to the smtp server and gets the information.
Well another example is IRC

Now, I haven't seen irc available over http or www. Messengers work in a similar way too. Though, now Yahoo and MSN have started web based messengers but then again, you just get a java applet of the client over http but the service uses a different protocol.

Here's the line from that article

The Internet, not the Web, is also used for e-mail, which relies on SMTP

ok , thanx . this doubt is cleared.
what about rest??? especially that virus one ?? please gimme one line definitions of all three: virus , worm , trojan.

*searchsecurity.techtarget.com/sDefinition/0,290660,sid14_gci213386,00.html
Viruses might corrupt or delete data on ur computer, use ur e-mail program to spread itself to other computers, or even erase everything on ur hard disk.
Trojans r used to steal ur data, mail it to the trojan creator etc.

So in short viruses cause active destruction and trojans cause passive destruction!! And according to me trojans r the worst type of infections.

Virus: Spreads from pc to pc and run without notify the user.

Trojan: mimics like a good program but when a user run them, they start something else in background. They usually steal data.

Worms: Infect only networks and try to make the whole network down.

Thanx mediator and vishal .
One Doubt left.
If make a LAN in a lab , can it be called an intranet ????

LAN is always an intranet. Doesn't matter if its a lab.

^^ u sure ???
I still have doubts because some people say intranet should use standard TCP/IP protocols and some say that it should be connected to net but ofcourse with restricted access to intranet.

No I was kidding/lieing!.....ofcors I'm sure!

Basically intranet is a network of a company/organisation. A company may employ various subnets. There may be a network A of managers, B of designers, C of programmers, D of freshers. There may be restrictions that C and D may be isolated. The tiniest unit of a network is called LAN.

A,B,C,D are all LANs.
If B,C,D come under A then A has 3 active subnets. In such a case A cannot be called a LAN then. It is a network having subnet(work)s. The whole system is called an intranet. It may be connected to the rest of the world or it may be isolated.
I hope I was clear! So LAN is intranet.

mediator said:
LAN is always an intranet. Doesn't matter if its a lab.

Nope ..LAN is not Always an Intranet.
Yes agreed they are used synonymous.But thats a loose term when Technicians are involved. Heres Why ?
Intranets are made on LANS, WANS and MANS. LAN network uses regular TCP/IP protocols and doesnot use all the regular internet protocols like HTTP, MIME, etc that intranets do.
So...LAN are not always an Intranet . For example take a simple computer to printer setup. Same thing for Wide Area Networks or WAN.

And who said LAN doesn't use regular http/mime protocols? Your Yahoo Answers? Gosh u copied the whole thing (answer 2 and answer 4 mainly)???

Have u ever set up a simple DNS server on a LAN giving names to each computer? Have u ever done "*computer_A" that redirects u to the web server on A? TCP/IP being the standard is used in all the computers. Across LAN what can't u use? http,ftp,telnet,ssh,smtp?

Here's a line from this pdf

Intranet refers to a LAN that uses Internet technology. In the same way, an extranet refers to a WAN that uses Internet technology.

Now if a LAN doesn't use the internet technology and is using some secret technology then obviously it can't be referred as an intranet. And I'm not talking about some secret technology.

So please don't go by what some sites say. Please refer to some standard books like "networks by Forouzan", "Tcp/IP by forouzan" and get ur confusion cleared!

Vishal Gupta said:
Virus: Spreads from pc to pc and run without notify the user.

Trojan: mimics like a good program but when a user run them, they start something else in background. They usually steal data.

Small correction
1.Virus once needs a user trigger(must) then they multiply withouy user intervention. Genrally virus activity is limited to single PC until user do not sent some infected data on remate m/c, they can't spread to n/w by there own.

2.Trojan do not steal data always they are generally ment to make some port open on host pc so that sender can invade the host pc.