A seemingly dumb question, sure, but I ask it regardless. A few days ago, it was my understanding that the internet worked like this: Websites and their contents are stored on servers, and accessed by users (like me) through a request sent through my ISP. My request would arrive, and the server would show what I asked for (most of the time, anyway). After watching A recent Ted Talk, that explanation seems... incomplete somehow.
In the video it's mentioned how one creative ISP decided to block Youtube by claiming to be Youtube, then just not doing anything with the incoming requests. What gets me is that their shenanigans somehow rippled out of their country and effectively took down Youtube for millions upon millions of people. I don't quite understand how that could work, and it doesn't really fit my previous assumption very well. Help me out here?
That case probably involes DNS (Domain Name System) Basically, when you put in "youtube.com", there has to be a way for computers to find out where exactly the servers for "youtube.com" are. Basically, they do that by sending "youtube.com" off to a DNS server, which returns an IP address for the servers hosting that site (173.194.33.6). Basically, like looking someone up in a phone book, you send a name, it sends back a number.
This is useful, not just because names are easier to remember, but because it means a site can change servers, host their site from a different location, a different provider, set up mirror servers so someone can access a server that's closer to them, etc., while still allowing people to find their site. The IP address might change with each of those things, but the name can remain the same, because they tell the DNS servers where the new location is, the new IP address. So people can just keep on using the same name to find the site, without even needing to be aware that there was a change to the number.
There are a whole bunch of DNS servers spread out around all over the place. So when the IP address for a site is updated at a DNS server, that information is then sent around to other DNS servers, in order to keep them up to date, to make sure they all have the same information, that they're all working with a consistent phone book.
Basically, in that instance they tried blocking youtube by editing the DNS entry. i.e. They went into the phonebook and changed the number, so that when people who were using that DNS server tried to go to youtube, it returned a address that pointed to their own servers, or the middle of nowhere, or something, rather than the actual youtube servers. This ended up rippling out, because their DNS ended up broadcasting this information to other DNS servers as an update to where that site was located, and so other DNS servers, being a bit overly trustworthy, updated their own records to match.
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Topic: How does the internet work? (Read 1106 times)