What Is My IP Here? Probably A Quick Answer

Discussion in 'MacBook Pro' started by rmbrown09, Aug 11, 2010.

  1. rmbrown09 macrumors 6502a

    rmbrown09

    Joined:
    Jan 25, 2010
    #1
    Well I am not sure what to make of all this, I am connected to the internet via a Airport Extreme, and sites that tell you your IP say

    [​IMG]

    But when I run ifconfig | grep "inet" in Terminal, I get this stuff

    So what exactly is this telling me??
    Thanks

    [​IMG]
     
  2. iBookG4user macrumors 604

    iBookG4user

    Joined:
    Jun 27, 2006
    Location:
    Seattle, WA
    #2
    The first is your external ip address and the second is your internal ip address.
     
  3. rmbrown09 thread starter macrumors 6502a

    rmbrown09

    Joined:
    Jan 25, 2010
    #3
    Sorry but what does that mean? Does the internal have something to do with the MAC
     
  4. crypticlineage macrumors regular

    Joined:
    Jun 24, 2010
    #4
    Your apartment or your office has an internal network where they assign a private ip to your computer. However when your computer talks to the world outside the internal network, the traffic is routed through an external ip address belonging to a gateway or router.

    This way, they restrict the amount of unwarranted traffic (spammers, hackers, or you running various services like website/ftp etc).

    This is why you have two ip addresses. The internal ip addresses always start with numbers like 192.168 or 10.200 etc.
     
  5. rmbrown09 thread starter macrumors 6502a

    rmbrown09

    Joined:
    Jan 25, 2010
    #5
    Ah I see, so the one that is 127.whatever is my external
    and then there are 4 different ones with the 192..... 2 are netmask and 2 are broadcast. Plus there is the 10..

    Plus why does it seem the external is different than what the websites tell me?? is that a different address too? I was thinking the external is basically the IP of the router?
     
  6. robvas macrumors 68020

    Joined:
    Mar 29, 2009
    Location:
    USA
    #6
    Research 'NAT'

    By just giving the router an IP address, you can use 1 IP address to connect many, many computers to the Internet. It is a much better way to get computers onto the Internet, as there are a limited amount of IP addresses. You're basically sharing the external IP address with the other computers.

    It's not perfect, because you have to do tricks if you want to run a server on that external IP address. But for just surfing the Internet, it works great.
     
  7. Peace macrumors Core

    Peace

    Joined:
    Apr 1, 2005
    Location:
    Space--The ONLY Frontier
    #7
    To put it simple. Your router ( airport ) is a DHCP server that uses NAT. Network Address Translation. It allows the external IP ( The real one that is seen on the internet and is assigned to your modem by your ISP ) to translate it to a loop-back address ( the 10.*,192.* ). This allows you to see the internet from behind a DHCP server and translates the IP from an external one to an internal one. Or called a loop-back IP.

    A loop-back address is for LAN ( local area networks ) only.

    So when you go to the real internet a website ( normally ) sees the address of your Cable,DSL modem.

    Is that confusing enough ? :)
     
  8. rmbrown09 thread starter macrumors 6502a

    rmbrown09

    Joined:
    Jan 25, 2010
    #8
    I see ( I think)
    Router flips me a different IP, along with everyone else on it. But we all broadcast the same thing? there are probably about 37 macs on this airport. (and about 5 phones)

    last Q,
    so my external..does the airport change that and that is what the websites see...


    so

    Internal<External<Airport or...
     
  9. Peace macrumors Core

    Peace

    Joined:
    Apr 1, 2005
    Location:
    Space--The ONLY Frontier
    #9
    The router assigns every device on the local network an internal IP.

    The modem is assigned an external IP from your ISP.

    Person A doesn't see what person B sees because they are assigned a different IP.

    The person with admin rights on the Airport can look at the config logs and see what IP other devices on the router are at.
     
  10. robvas macrumors 68020

    Joined:
    Mar 29, 2009
    Location:
    USA
    #10
    I drew up a quick diagram:

    [​IMG]

    As far as the rest of the internet is concerned, any computer coming from the internal network is seen as the external IP address of the Airport (which is the Cable/DSL router in the diagram)
     
  11. rmbrown09 thread starter macrumors 6502a

    rmbrown09

    Joined:
    Jan 25, 2010
    #11
    Awesome thanks!
     

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