IP address question

david55david55
edited February 2005 in Science & Tech
Hi all.

I'm wondering if this is normal or not?

I have 2 computers connected to an Encore hub (for internet access only) and the hub connects to a Qwest/Actiontec dsl modem. When I open 'winipconfig' seperatly on each computer it shows a different ip address on each computer which seems normal I think. When I go to any "whatsmyip" site the ip address shows as being the same for both computers yet completly different then either ip address showing up in winipcfg on either computer.

I pinged all ip addresses and the 2 in winipcfg ping to me and the ip address showing on "whatsmyip" pings to another state like it really is not mine.

So I'm lost?

Comments

  • ShortyShorty Manchester, UK Icrontian
    edited February 2005
    The one that is always the same on both is the WAN address assigned to you by your internet service provider :)

    The other two addresses are LAN (local network) addresses that are unique to your network behind the router :)
  • DexterDexter Vancouver, BC Canada
    edited February 2005
    Just in case that did not quite make sense, think of a router as being like a telephone system in an office.

    - When someone from the outside dials your office, they dial one main phone number, and it goes to a switchboard. The receptionist answers it, finds out who it is for, and then routes the call to the appropriate person's telephone by forwarding the call to that particular telephone extension.

    - When someone at one desk wants to call someone at another desk, they do not need to use an outside line and dial all the digits. They can use an "inside line", dial a 2, 3 or 4 digit extension number, and speak to the other local person without having to have the call go outside the building.

    - When someone at a desk wants to call outside, they need to dial 9 first to get routed to an outside line, and have to dial all the numbers (eg 9,555-1234)

    Your router works the same way. The Wide Area Network (WAN) IP address is the "outside phone number." The router knows where to send each "call", and uses the Local Area Network (LAN) IP address to route the call to the right computer (telephone.) When you access a shared folder on another computer in your network, or use a networked printer, you don't ever leave your internal LAN, your router just keeps the "call" local. When you open a web browser to access the internet, the router "dials 9" for you, then "dials the outside phone number."

    The graphic below gives you more of an idea how this works as well.

    Dexter...
  • david55david55
    edited February 2005
    Hey that's great!

    Between both replies I think I understand perfectly. With what your saying then I can guess that there is no security issues and this is all normal. What freaked me out after I wrote the first post was I called a friend who lives a half mile away on the same isp and her LAN address was exactly the same as one of mine but again I would guess that is not unusual at all.

    What is confusing is you would think that in winipcfg it would say "LAN address" instead of "ip address", then I may not have needed to post the question.

    One more question I have, maybe not for here, but I'll give it a shot anyway is, is there a simple way to find if I have a static or dynamic ip?

    Thanks all.
  • DexterDexter Vancouver, BC Canada
    edited February 2005
    The computer itself cannot discern whether you are on a WAN or a LAN. If you had only one computer, and no router, just a direct connection to the internet, you would be on a LAN. The IP address reported by your computer would then be a WAN address. Hence, the computer does not make any such distinction, it simply reports the IP address at the ethernet adaptor, whatever that number happens to be.

    If you are paying for basic home service through DSL or cable, you are most lilkely going to have a dynamic address. In order to get a static address, you normally have to pay extra. Many businesses pay extra for a static IP if they want to run a web server, ftp server, VPN, etc at their office. Most home connections are dynamic.

    Having said that though, some service providers, especially cable ones, tend to assign addresses on a "semi-static" basis. No matter how many times you release and renew your IP, it is going to keep giving you the same address. However, once in a while, they may shake up the addresses a little, and your address will change. So you may have the same address for weeks or even months, but then suddenly it changes.

    Dexter...
  • david55david55
    edited February 2005
    The computer itself cannot discern whether you are on a WAN or a LAN. If you had only one computer, and no router, just a direct connection to the internet, you would be on a LAN. The IP address reported by your computer would then be a WAN address. Hence, the computer does not make any such distinction, it simply reports the IP address at the ethernet adaptor, whatever that number happens to be.

    The above info is kind of confusing to me but I will keep reading it until I understand it.. :confused: Thanks for the help.

    About static/dynamic;
    I'm now with Qwest DSL after being with Comcast high speed cable for 2 years. I had Qwest DSL years back and was able to just recycle the modem to get a new IP address, now I can't do thatwith them but I believe it is still dynamic like you say. Comcast though charges for additional IPs ($5.00 for 3) so I'm sure they are static.

    Anyway, thanks again for the help, "THE FAST HELP". It is nice to get answers in a day or less unlike some boards where it takes days, months or never!
  • DexterDexter Vancouver, BC Canada
    edited February 2005
    david55 wrote:
    The computer itself cannot discern whether you are on a WAN or a LAN. If you had only one computer, and no router, just a direct connection to the internet, you would be on a LAN. The IP address reported by your computer would then be a WAN address. Hence, the computer does not make any such distinction, it simply reports the IP address at the ethernet adaptor, whatever that number happens to be.

    The above info is kind of confusing to me but I will keep reading it until I understand it.. :confused: Thanks for the help.

    Let me try again then.... :)

    The computer itself has no clue whether you are on a LAN (plugged in to a router) or a WAN (plugged directly into the cable modem / DSL modem.) All it knows is whether you are connected or not, whether that address was assigned dynamically from an external source (router or ISP) or hardcoded into the network properties. When you query your local IP address using an IPCONFIG/ALL command, the computer just tells you what it knows: the IP address it has at the network adaptor. It just cannot tell you where that address came from (a LAN router or a WAN ISP.)

    Dexter...
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