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Quick Tech Question For You IT Boffins

Discussion in 'Non-Music Chat' started by MarcPollitt84, Nov 7, 2014.

  1. MarcPollitt84

    MarcPollitt84 Well-Known Member

    Favourite Bands:
    Two Gallants
    Can someone tell me, in the manner you might explain to a 10 year old, what an IP address is?

    I think I know but would like some clarification and a couple of possible follow up questions.

    Ta
     
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  3. In simple terms it's your computer/phone etc's real address on the internet... but I know they can change dynamically and I don't get that bit.
     
  4. MarcPollitt84

    MarcPollitt84 Well-Known Member

    Favourite Bands:
    Two Gallants
    Is it possible for two different people to have the same IP address? Like if they had the same ISP or shared a WiFi network or something?
     
  5. They should be device specific but I know they sometimes aren't. Not much help!
     
  6. MarcPollitt84

    MarcPollitt84 Well-Known Member

    Favourite Bands:
    Two Gallants
    Ha!

    So, say just for example, two separate users on an internet forum had the same IP for a couple of posts that wouldnt necessarily mean they were the same person?
     
  7. If they didn't live together/work at the same place - it should be unlikely that IP's would match.... but i'm 80% speculating.
     
  8. Also I think university networks might have a single IP etc.
     
  9. Brader

    Brader New Member

    I always thought of it as a postcode. Like, multiple people could live at that address (devices) but in essence they would be existing from one code. However I'm not overly tech savvy and it's not something I think about a lot.
     
  10. Brader

    Brader New Member

    I always thought of it as a postcode. Like, multiple people could live at that address (devices) but in essence they would be existing from one code. However I'm not overly tech savvy and it's not something I think about a lot.
     
  11. MarcPollitt84

    MarcPollitt84 Well-Known Member

    Favourite Bands:
    Two Gallants
    Ah right, so just cos one person has posted from the same IP as another a couple of times doesn't mean they are the one and the same?

    I didn't think so to be honest but I thought it might be worth asking.
     
  12. Within reason,

    Two people living in Leeds both using Virgin (or whatever) maybe... two people with nothing in common and coincidence starts to get pretty unlikely.
     
  13. superficial_guy

    superficial_guy New Member

    Depends whether you are referring to your private or public IP address. Only one computer per network can have a particular IP address at a given time. It is most commonly in the form of 192.168.xxx.xxx.

    Your public IP address is how your entire network is identified to the world. Every single network device that is hooked up to a particular internet connection has the same external IP address. However, only your network has this external IP address; no other network has it. If you do a whatismyip search, the IP that comes back is your public address and everyone on your network will have this.

    For example, if you have internet at your house on 2 computers, you'd have a router from your Internet service provider and then the two computers connected to that. One computer has an internal IP address of 192.168.1.10, the other has an internal IP address of 192.168.1.11, and the router has a similar internal IP addresses. All 3 devices have the exact same external IP address.
     
  14. davelms

    davelms Member

    Favourite Bands:
    Not Telling
    To follow on from the previous reply, there are static IP public addresses which you and only you have and you will know what it is before you connect; or dynamic IP public addresses which you obtain at the time of connecting to your ISP and which your ISP allocates to you randomly and you won't know what it is beforehand.

    You may be given a static IP public address that someone else used to possess, but for the period of your contract with whoever-assigned-you-the-static-IP-address no one else but you (and your household / whoever uses your router) will have that public IP address - after you terminate your contract, your old public IP address may be given to someone else. Since contracts are usually for 6 months or more, such users may have this IP address for a long time. When you do an IP lookup using many of the online tools, it usually states in the ISP notes if it is a static IP (although it won't usually say who it's been given to).

    More likely you are given a dynamic public IP address which will change over time (even as often as hourly or daily - but this is rare, more likely to be seen with mobile operators than ADSL or cable) every time your router connects to your ISP - some routers have an "always on" option which means you are most likely to keep the same public IP address for a longer period. In such cases you could have the same public IP address for weeks. If you switch off your router, or do not have the "always on" enabled, or something else causes your connection to drop, you will find your public IP address may change as the ISP gives you another one and later gives yours to someone else. Your ISP has hundreds of thousands of these public IP addresses to give away at the time of connection. Note that even for dynamic IP addresses, due to the way that some of the networks are configured, you are likely to get the same IP address on reconnection if the time after it dropped is quick - your ISP will only mark your connection as "re-usable" after a certain period has elapsed after you stopped using it, and then it puts it back into its available pool. So even if you are on a dynamic IP address, you may find you keep the same one for a while, it really does depend on your ISP and their configuration (there are performance reasons why the ISP may want to balance keeping their pool of IP addresses at a certain level versus unnecessary reallocation of new ones).

    It is far more common for people to be on a dynamic IP address that may change over time than be on a static IP address that is fixed.

    There is another complexity, which is an outbound proxy that some organisations use (and some ISPs like AOL). This basically makes all users have an NON PUBLIC internal IP address and they all share exactly the same external public IP. So in those cases you can have many users all sharing the same IP address (just like a household sharing the same router). My company has such a set up in place, so every single one of our 7,000 employees worldwide has the same public IP address (which causes some trouble when visiting sites because it's shown to be a US-based IP address, so we always get the US version of sites!). So if you were to look up an IP address and find it belonged to a company, rather than an ISP, there is a greater probability that several different users are sharing that same public IP address.
     
  15. davelms

    davelms Member

    Favourite Bands:
    Not Telling
  16. MarcPollitt84

    MarcPollitt84 Well-Known Member

    Favourite Bands:
    Two Gallants
  17. MarcPollitt84

    MarcPollitt84 Well-Known Member

    Favourite Bands:
    Two Gallants
  18. Lavalas

    Lavalas Member

    Favourite Bands:
    Do Make Say Think
    I was once accused of having multiple log-ins on another forum which was spotted when I was apparently having a conversation with myself. After the other user name was pointed out to me (which closely resembled an actual name) I worked out that we had the same IP address because we worked for the same company but in different offices in different cities and I actually regularly attended the same meetings as this person without ever knowing we posted on the same forum... and I still haven't mentioned it. All a bit weird really.
     
  19. aej1

    aej1 Active Member

    If you are with Bt and you reboot everything you get a new IP address so sometimes it looks as if I an posting from somewhere else when I an not.
     

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