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How does Subnetting Work?
IP addresses and geographical locations

How does my IP address get assigned to me? Is there any ordering? For instance by time or by location or by queue? Who divvies up the IP addresses at each level, and what method do they use?

What do the individual parts of the IP address mean? (ex. 72.14.204.99) Does it move from least geographically specific at the left to most at the right?

I'm especially interested in understand the correlation between geographic location and IP address.

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migrated from stackoverflow.com Dec 9 '10 at 17:37

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marked as duplicate by Zoredache, Chris S, Chopper3 Dec 9 '10 at 17:54

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It's too broad, do you mean IP address as in the whole internet or your local LAN? –  The Elite Gentleman Dec 9 '10 at 17:37
    
Part of your question (Geo-location) is answered here: serverfault.com/questions/86793/… –  l0c0b0x Dec 9 '10 at 18:00

1 Answer 1

up vote 2 down vote accepted

They don't really mean anything. There are certain reserved blocks, which are good to know

The following are reserved for "private" networks. These only ever apply in LAN/WAN environments.

  • 10.0.0.0 – 10.255.255.255
  • 172.16.0.0 – 172.31.255.255
  • 192.168.0.0 – 192.168.255.255

The following addresses only ever apply to the local machine (the Loopback addresses):

  • 127.0.0.0-127.255.255.255 (addresses other than 127.0.0.1 are seldom used).

The 0.0.0.0 block is reserved for the "default route", for routing purposes.

Inversely 1.1.1.1 and 255.255.255.255 is used to signify broadcasting on all routes.

The 169.254.0.0 -169.254.255.255 block is reserved for Automatic Private IP Addressing

There are a number of other addresses that are reserved for INCAN, ARIN, etc. A partial list can be found here.

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That's a great start, but can you also comment on the method by which IP addresses are assigned? For instance, I know that someone gets a "block" of IP addresses from someone else. And then someone divvies them up and gives me one. Who are all the someones and what method do they use to divvy up addresses? –  John Berryman Dec 9 '10 at 17:59
    
@John Berryman, IANA is the from (iana.org) and subnetting is the how serverfault.com/questions/49765/how-does-subnetting-work. –  Zoredache Dec 9 '10 at 18:24
    
@John Berryman: It's pretty much random. Your ISP has a certain block of addresses, and they assign them in smaller blocks to roughly geographic areas. But another ISP may have a contiguous block that they assign to a totally different area. And both can reassign the blocks pretty much at will if they need to. If you want to know what block is in what area, you can check an IP Geolocation database: ipinfodb.com/ip_database.php but they're assembled from reported/researched data, not from any over-riding algorithm. –  Satanicpuppy Dec 9 '10 at 23:02

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