I’m sort of aware of DNS, IP, ARP – all the high level internet stuff.
But if computers look for each other, how do they choose which cable should they send info through? How DNS server chooses “the road” to another computer? Or is it pushing signals everywhere it can and other computers ignore what’s not for them?
In: Technology
Routers create routing tables, which contain the best route for the packet to travel. Best, in this case, meaning quickest / shortest path to the destination. These tables are updated on a regular basis to route around outrages.
It kind of works like the mail.
You send a data packet and write the IP adress of the receiver on it. Your router sends it to the local access point, they send it to the correct region, there the local access points sends it to the correct receiver.
Most computers have precisely one cable to send through, so the answer is trivial. The things that are concerned with routing stuff between multiple cables are… the **routers**.
Those have a table with the list of networks they have a port in, and a list of networks they can reach (and which port to use for them). They usually talk to other routers connected to their networks and tell each other about the networks they can reach so other routers know which way to pass packets. Usually one router in an organization (that isn’t an ISP) will have a port that’s simply designated “towards 0.0.0.0/0” a.k.a. “internet this way”. It’s called the default route. If none of the routers who exchange messages know where that packet should go, it gets passed to this router and sent out of that port in the hopes that the routers on the other end will know how to guide that packet towards its destination.
>How DNS server chooses “the road” to another computer?
* It doesn’t.
* DNS just translates domain names like [www.google.com](https://www.google.com) to IP addresses like 172.217.11.36
* It gives that back to your browser and basically says “good luck!”
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