What is the difference between a LAN and Intranet?

Question

My current understanding is that a LAN is a 2 or more computers connected within a local geographical location.

I always thought intranet was the webpages accessed on a LAN network but that appears to be called intraweb.

So what is the difference between intranet and LAN?

Solution 1

A LAN is a set of computers that all have a NIC that's connected with the same subnet mask (e.g. 255.255.255.0), and which are on the same network (e.g. 192.168.0.X). One way this is easily done is connecting a number of computers to the same switch/switch stack, or the switch part (the LAN ports) of a home router.

When this happens, each computer on the LAN can send broadcast traffic to all other computers on the LAN, and talk to any other computer when the IP address is known, if the computer itself is not blocking traffic from the LAN.

I always thought intranet was the webpages accessed on a LAN network but that appears to be called intraweb.

Well, in a LAN you can have servers (in addition to standard PCs/laptops) that offer services to PCs/laptops on the LAN and LAN only. A web server could be one of those services, and there may be other things like a file server, Lync or chat server, etc. Intranet would technically be the entire collection of servers meant to be accessed by computer on the LAN (but not available from the general Internet) - and intraweb could be the web server only from the intranet.

Solution 2

An intranet is a private network. Usually intranet is not used as a term for home networks, but technically every LAN is an intranet, or part of one. A Local Area Network is local. An intranet doesn't have to be local, it can be the private network of a company with 3 offices which are all linked up with a Wide Area Network.

Solution 3

In addition to what Peter said, we humans typically use differing terminology to identify function rather than to define something.

If you wanted to go with the raw definition, every network in the world is a small internet, and every internet/intranet is a LAN/WAN just composing of different rules and some variations in the protocols, usually to combat security issues.

However, if you look at the terminology as a term describing function, as in the term defines its purpose rather than defining its fundamental nature, then it's easier to understand. Intranet is a LAN between computers who's function is to be utilized as a local internet. The protocols will almost assuredly be different than a normal LAN/WAN because a normal LAN/WAN is typically meant to severely restrict communications between computers on the network, whereas an intranet would want to be able to do everything the internet does in communications between computers.

It's like when you call a child a toddler or a fetus. The fundamental nature of the object is still the same, but the terminology describes the function. As a fetus, the child is developing through the in-womb stages, as a toddler, the child is developing through the stages of barely learning to walk, focus, and understand speech as well as form words in a rudimentary fashion. (Yes, I intentionally chose this example because both, it's valid and demonstrates a point that perhaps might save someone's life.)

The protocols will be much more complex for an intranet because it has to focus both on allowing connectivity in every feasible way that the internet does, plus prevent unwarranted remote access.

Comments

[MC10]

You can find some information here: superuser.com/questions/135164/…

[Tim]

Wouldn't that then be an extranet? and have an extraweb?

[MC10]

An extranet can be a subsection of an intranet. An extranet is a website that allows controlled access to partners, vendors and suppliers or an authorized set of customers - normally to a subset of the information accessible from an organization's intranet.