How do all servers across the world ensure unique IP addresses?

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I could be totally wrong here, but I’ve always been under the impression that IP addresses are unique in that for every address, there is one and only one server/computer, and viceversa. How do you accomplish this given all the different manufacturers, countries’ internet protocols, etc.?

In: Technology

6 Answers

Anonymous 0 Comments

Others have done a good job covering the basics, so I’ll go into more of the technical details.

The right to use Public IPs is assigned to companies and groups by organizations like ARIN (North America) and RIPE (Europe).

Qualifying organizations (Large companies and ISPs) apply for and pay a fee to use IP address space and are assigned blocks of unique IP addresses that they are free to use as they see fit. This address space is advertised to the rest of the internet using BGP (Border Gateway Protocol) which tells the internet where those IPs are located and how to get there.

If you attempt to advertise IP space that doesn’t belong to you (effectively stealing IPs) your peering partners (who your WAN network is connected to) will soon recognize that and filter out (block) the advertisements effectively dropping your network off the face of the internet until you fix it. This can cause serious havoc to the internet and is taken very seriously.

However the vast majority of organizations and private individuals are too small to warrant having blocks of IPs dedicated to them (the smallest issueable blocks are 256 IPs, while most companies only need 1 or 2). So instead it’s more practical for most companies and persons to effectively lease IP addresses from larger organizations (ISPs).

When you make a connection via an ISP they lease you a temporary unique IP address which is assigned to your modem. In the case of businesses (for an additional fee) a static or permanent unchanging address(es) can be assigned to the service. These addresses are unique and unchanging and therefore better suited for hosting websites and the like.

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