Topic: A question about ip address

[Michelle]

Not sure if this is the right place for this but .... anyway.

You know the ip address does anyone know what the numbers mean, is it all just the area and if two ip addresses are the same does that mean its the same computer or just the same house? or work place or would that be more like this

130.45.56.123
130.45.56.200

Can anyone advise me on this please?

[measter]

a computers ip address is similer to your home address. every computer has one, which tells the server where to send to data. thats pretty much all i can think of.

[Sandra]

The first two groups are the ISPs Michelle, so they are a little like saying which county you are in on a postal address, the second two are the specific computer that is connected to that ISP and is generated by the ISP itself.
This is for a WAN (Wide Area Network), ie the internet itself.
If you have a LAN (Local Area network), ie a home or office network, then you get the WAN IP from your ISP then your network assigns a different IP to each PC that shares that network, commonly starting with 192 or 10 as the first group of numbers, which are completely seperate from the ISP one, a bit like a block of flats having the same post code but an individual number for each flat.
Hope this helps you understand it a little more clearly  

[measter]

the network address is that single computers address. while an internet ip is one given to your pc by your isp. also, from what i'v seen for network addresses they normally start with 192.168.

[Michelle]

Ah, thanks guys, I'm getting there, its still a bit confusing to me cos I'm not certain of the difference between WAN and LAN.


okay - so is there a list of numbers so that you can see what area someone is from using the first two numbers?

And say it seems that there are two people online with the completely the same numbers, how could that happen if each computer would have its own number, oh  okay so that would be if they are on a network with the one isp would it?

Sorry to be thick, I've often wondered about this.

[measter]

most dial up isps and some broadband ones use a dynamic ip. a dynamic ip changes every time you log onto the internet. whereas a static ip stays the same all the time.

[Sandra]

You cant see the area Michelle, only the ISP that they are with, so sometimes it will narrow it down to a country, thats the closest that you can identify the area to easily.
Any single pc connected to the internet has its own unique IP address but if you are on dial up or have a "Dynamic" IP this will be a different one each time that you connect to the internet, but the first two groups of numbers will always be the same as that denotes the ISP that you are connected to.
If you are on a broadband connection, you often get a "Static" IP so that will always be the same even if you reconnect, handy for people running a server or website.
No two PCs anywhere in the world can have the same IP at the same time, but with dynamic IPs then you may have one IP address today and someone else may get that same IP after you close your connection  

[Michelle]

Okay now I'm really confused  

How come someone I knew once could tell me what area people were in? And you can get into places again because your ip address was logged in there, how can that happen if it changes each time?   I thought you always had the same ip address. Is that just using the first two numbers (which do stay the same?)

So dynamic ones change and static ones stay the same right?

How do you know if you are dynamic or static ?

[Sandra]

You may find this interesting Michelle :

IP addressing

An IP address is 32 bits wide, and as discussed, it is composed of two parts: the network number, and the host number [1, 2, 3]. By convention, it is expressed as four decimal numbers separated by periods, such as "200.1.2.3" representing the decimal value of each of the four bytes. Valid addresses thus range from 0.0.0.0 to 255.255.255.255, a total of about 4.3 billion addresses.

I believe that there was some concern recently about us running out of available IP addresses, although with a population of around 6 billion worldwide, you would have thought that 4.3 billion would be sufficient  

For a long page with more information on IPs, wan and lan and where I copied the above bit from, see here :

http://www.sangoma.com/fguide.htm

[Sandra]

Okay now I'm really confused  

1: How come someone I knew once could tell me what area people were in?  

2: So dynamic ones change and static ones stay the same right?

3: How do you know if you are dynamic or static ?

1: You can use something like this to trace an IP with varying success as to how much you can narrow down a location.

http://www.samspade.org/

2: Correct  

3: As far as I know there are no dial up connections that do Static IPs, if you are on BB you sometimes get the option to have a Static IP, usually at extra cost, although to confuse you even more, I have a Dynamic address which has never changed in 18 months or so and is referred to as a "Sticky Dynamic" IP  

[Michelle]

Sticky Dynamic

I'm sure my ip is always the same ? maybe not then.

Thanks for all that sandra, (and maester) I will have a look at that webpage.

You know what its like when you just HAVE to know something!

Its a bit like when you just have to hear that piece of music that has been going round in your head all day!



 

[Michelle]

Just wanted to say Sandra was right, not that I doubted her for a second of course  8)  

My ip changes all the time, the first 2 sets of numbers do stay the same.

Thats that just about cleared up then.

The only thing I don't get is how two people can be on line with the same number, as everything I've read or been told suggests this is not possible unless they are on the same computer, which would be difficult but not impossible I guess if it was just one person pretending to be two people. ah there's my answer

 
     

[Adept]

3: As far as I know there are no dial up connections that do Static IPs

Many do actually Sandra. Demon Internet for instance have always had static IPs on all their dial-up accounts.

Michelle, a website I often use to lookup IP addresses is http://www.network-tools.com It gives you all sorts of information about any IP address you enter into it.

It is possible for more than one person to appear to have the same IP address if they are on a network connected to a router or proxy server. The router or proxy shares one IP address amongst many users using something called Network Address Translation (NAT)

[Michelle]

ahhh I see, thanks adept.

ohh I'll have a look at that site then.  

edit: oops

[ketamininja]

Here's another site:

http://www.geobytes.com/IpLocator.htm

aaa.bbb.ccc.ddd = IP address

aaa.bbb = ISP address (this is registered with the top boys).
ccc = ISP subnet (they are allowed to have up to 255 subnets for their aaa.bbb number).
ddd = YOUR ip number (again 255 allowed).

So you can see that for each aaa.bbb number, there can only be 255 x 255 unique IP addresses (or users). This is why ISPs may have more than one aaa.bbb address.

DHCP is the ISP's IP management program. An IP address is assigned to you.

This IP address is given a time to live (TTL). It checks your pc every HALF TTL to see if you are still there. Addresses are usually leased for 12 - 24 hours. If you are still online after that time, your address will be renewed for another TTL. And so it goes on.

Its worth noting that "dynamic" IPs (so called because they always change) are still registered with DHCP usually. So this means even a dialup user CAN have the same IP always, as long as the log in before the TTL expires (when it expires, the address is released for ANYBODY eles to use).