I kinda get how it makes sense on a local network, because it’s kinda like a list of the devices that are connected to it and your trying to communicate with other machines connected together in that same list. But this feels like a really surface level understanding and I don’t know what I’m missing.
I understand that they’re a string of 4 digits from 1-255, such as 192.168.1.1 being really common for home networks. But I don’t know what the numbers each mean. I think 192 in this case is a reserved value for home use? Same with 10? And the last number is basically the number of the device on the network I think. But I don’t understand the numbers for x.168.1.x
What I really don’t understand is how public IPs work. You hear online about not leaking or sharing your public IP or it can be used to find (pretty close to) where you live. How? How are they assigned to the billions of connected devices in the world?
I’ve been watching videos about trying to set up a FOSS router because it’s really interesting, but IPs seem like dark magic to me
In: Technology
Internet service providers or big companies like Google buy blocks of IP addresses. An IP block can be something like all IP addresses in the form of 123.x.x.x or something smaller like 123.1.2.x
The owner of these IP blocks can assign them to their devices or customers however they want. For Internet customers the assigned IPs often change or multiple users share a single IP addresses (via technologies like CNAT).
There are some special IP blocks like 192.168.x.x or 10.x.x.x which don’t get assigned to organizations, but are reserved for use in internal networks. There are also some other blocks (like 127.0.x.x) which are reserved for other special applications.
An message in the Internet (in form of a TCP package), has a sender and a receiver IP addresses, and that tells the routers, which the message passes, where to send the message.
In the Internet there is actually another important protocol called BGP, which does the mapping between IP addresses and (physical) networks/routers. Basically an Internet provider tells other Internet providers, if you wanna send a message to 123.123.123.1 then send it to router 1235 in my network. From this the other routers can derive where to send a package too, even if they can not directly reach router 1235 (and maybe need to send it to router 432, which then forwards it to router 1235).
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