Imagine if I bought an IP address…
How would I actually be able to use it as my computer’s IP address?
I’ve searched the whole internet but haven't found anyone explaining how to actually use a purchased IP address.
I’m thinking of buying an IP because I think my ISP blocks port and don't like the ISP.
by bought an ip address I meant a whole block, would it be possible to actually use the ips that I bought instead of asking the isp for giving me one? Would I have to become an internet provider
Yes it would be possible, but only with the ISP's cooperation. They're the ones who physically carry the packets back and forth. Having your own address won't bypass that.
For IPv4, your address block must be at least /24 – smaller blocks (longer prefixes) will just be ignored Internet-wide. Similarly for IPv6 the minimum size is /48.
Each advertisement takes up memory space in ISP routers – not just your ISP but every ISP which participates – so they all have collectively agreed to filter advertisements smaller than (prefixes longer than) a certain size.
You will also need to get an autonomous system number (ASN) for your network. These are issued by RIRs such as RIPE or ARIN, costing around $100/year. Usually the same place that sold you the address block will help you get an AS number.
(In some regions, AS numbers are only issued to networks that intend to "multi-home", i.e. announce through two or more ISPs simultaneously, but this is mostly a formality.)
Some carriers might offer to advertise your address block with their ASN instead, saving you some bureaucracy. I think this simpler form of of "Bring Your Own IP" service is common among cloud hosting providers (although there are some which do full BGP too).
You will need to purchase BGP transit service from your ISP. Usually this is limited to "enterprise" or "large business" plans.
The ISP is needed because they provide you with the physical connection.
(Sure, you can set up private one-to-one peerings, but eventually you'll rely on some company to act as a 'hub' to provide a broader connectivity. There are "carrier" ISPs that focus on providing BGP transit service and connecting only whole networks, like companies or smaller ISPs.)
If your local ISPs don't offer BGP service, you could set up a BGP peering elsewhere (e.g. on a cloud server or at an IX) and then tunnel the IPs over your regular ISP connection – literally building your own VPN – though of course this way you'll be physically limited to what your regular ISP connection can do. Still, sometimes there are advantages to doing this, especially if your local ISP has a good direct connection to some cloud hosting company but uses a bad transit provider overall.
Finally, you will need a router that can be configured to speak BGP to the ISP's router – this is how it actually advertises that the address block should be routed to you, and this advertisement is propagated around the world through BGP links.
BGP is not limited to large enterprise equipment; though you won't find it on a home wifi router, but it is a relatively "cheap" feature. In a pinch, Linux or BSD systems can be used as BGP-capable routers.
Will this help you bypass ISP-imposed filters? Technically no. All your traffic still has to physically go through the ISP's routers and other infrastructure. Though they'll probably be much more willing to remove the filters for an "enterprise BGP" customer than for a "home residential" line, because you'll be paying more.
Does this make you "an internet provider"? In a sense yes – you're now connected to the Internet the same way ISPs do, and many places will actually show you as being your own ISP. Though of course you're not actually required to provide internet access to anyone (and depending on what kind of address range and what kind of BGP connection you have, you might not even be allowed to).
Imagine if I bought an IP address…
How would I actually be able to use it as my computer’s IP address?
You would contact your two or more Internet service providers to add the IP address block you purchased to the set you are permitted to advertise. You would then configure your gateway router's BGP to advertise that block.
I’ve searched the whole internet but haven't found anyone explaining how to actually use a purchased IP address.
You really aren't supposed to purchase IP addresses, but if you purchase a company that owns a block of IP addresses, that will accomplish the same thing. You still have to meet the requirements yourself though.
I’m thinking of buying an IP because I think my ISP blocks port and don't like the ISP.
That doesn't make any sense. Blocked ports are a property of your connection, not your IP address. And I doubt your current connection supports BGP (or any dynamic routing) anyway, so you couldn't use your own addresses with it.
If the routing and connection are going to stay the same, what's a different IP address going to do for you?
I have one for you. 172.16.16.172. I will sell it to you for $172.16.
Okay, seriously now... DON'T DO IT.
Like the famous saying of buying the Brooklyn Bridge, or when Universal Studios tried to sue Nintendo over the use of King Kong, no private entity should be selling you an IP address.
An IPv4 address is basically a fancy way of writing a number between zero and 4,294,967,295. Didn't know that? Try using a Microsoft Windows computer and running:
C:\> ping 134744072
Pinging 8.8.8.8 with 32 bytes of data:
Reply from 8.8.8.8: bytes=32 time=10ms TTL=116
Reply from 8.8.8.8: bytes=32 time=10ms TTL=116
Reply from 8.8.8.8: bytes=32 time=10ms TTL=116
Reply from 8.8.8.8: bytes=32 time=10ms TTL=116
Ping statistics for 8.8.8.8:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 10ms, Maximum = 10ms, Average = 10ms
C:\>
See, 1,348,744,072 (which is 8x256x256x256+8x256x256+8x256+8x1) is really rather equivalent to 8.8.8.8 and Microsoft Windows's ping command even recognizes that.
Just like the government gives free ownership of numbers like seven (written English), 7 (Arabic numeral), you can't copyright the number seven, the number 7, siete (written Spanish), or VII (roman numeral), you likewise cannot own 0.0.0.7 or 8.8.8.8
What you can do is have some control over the number, based on the assignments from the Internet Assigned Numbers Authority who provided some decision making to the regional Internet registries (RIR's) such as ARIN (American Registration of Internet Numbers), who has allocated groups of numbers to certain organizations such as Internet Service Providers. There are some general rules in place, which are followed by the sort of consensus that makes the Internet work as well as it does.
And part of that consensus is that the address 172.16.16.172 is actually free for you to use, as specified by the Internet Engineering Task Force (IETF)'s Best Current Practice 5, which is basically the Request for Comments 1918 (a very minor update to RFC 1597). The public Internet won't accept it, but you may use it privately on your own Internal network, according to that standard.
So, my offer to sell it was clearly a joke. It's not mine to sell. Enjoy using it how you like. (Of course, getting other people to route the traffic to you might be an entirely different challenge. That does get covered by another Superuser question, How to redirect/route IP address to another IP address?.)
Basically, I will acknowledge there is something of a market for IP address blocks. Although, people are usually talking about "blocks", meaning larger groups of addresses, and not just a single address. IP addresses are often most sensibly/efficiently handled in groups of neighboring addresses, because of how Internet routing is designed. Basically, if someone sold you a single address, the rest of the Internet would still route such traffic to the group that the address is a part of. So the seller would still be involved. (That is, at least with traditional standard Unicast routing that we are most used to.) Since that seller would often still be handling bandwidth in order to route traffic to your address, they aren't really free of involvement with the address, so the address isn't really "sold" very fully. The closest thing would probably be when an Internet Service Provider provides access to a single "Static IP" address, often in exchange for a cost that is charged to a customer. But since the customer would lose access to that address once they stop subscribing to that cost, the customer never really had full ownership of the address.
Similar reading: who owns a domain name. (If anybody, the Internet Corporation for Assigned Names and Numbers (ICANN), although the referenced article basically indicates nobody owns them either.)
