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Frances Collins
1,610 PointsWhy isn't a DNS server sufficient to request website information from? There's also another server it's sent to?
The illustration shows the request is sent to a DNS (domain name server) and then another server (with an IP address) afterwards. Then it follows the same path back. Why the additional server, isn't one sufficient? Isn't all the information for the website contained on one server? Does the DNS server only keep domain names, literally, an all other information is on an additional server...so it acts sort of like a router?
4 Answers
Jason Anders
Treehouse Moderator 145,858 PointsHi Frances. Welcome to Treehouse.
In a way you are correct in that a DNS server acts like a router for all the information, but I would use an analogy of a Phone Book.
All websites (and devices attached to the internet) have a numerical address either using the IPv4 or IPv6 protocols. These are very different than the web address that you type into the address bar.
For example, when you come here, you type teamtreehouse.com. However, the actual website address is 173.247.98.20. Which one is easier to remember? Can you imagine all the websites you know... now imagine having to remember a number like that for all of them.
Now, back to your question. Yes, there needs to be two different servers. One stores the data and one tells the request how to get there. When you type in teamtreehouse.com, that is sent to a "Name Server" or DNS, the correct numeric address is found for the name you typed in and then it directs 'you' to the server that holds the data for the address. These servers aren't the same because of the shear volume of requests that run through a DNS, which is why (like Neil said), many sites employ at least 2 Domain Name Servers.
Name servers (DNS), however, are not part of the website, and sites do not generally have there own DNSs. Unlike what Neil said about Treehouse, those Name Servers listed are part of the hosting company Treehouse uses. You, yourself, also have Name Servers through your Internet Service Provider. Companies who provide access to the internet (Your ISP or your site's hosting service) provide the DNSs as a way for you to find a website and for a website to find you. They do this because it is them that connects you or your site to the internet).
I hope this helps. :)
Brandon York
2,302 PointsI took a few network engineering classing in college and the way that my teachers explained this to me is this: When you address a letter to your friend and put your letter(packet) in the mail, It doesn't go straight to your friends house. It first gets picked up by the mail man(Internet service provider). At this point it gets taken to the post office(DNS). The post office then figures out(resolves) where the letter is going(IP address). Then and only then does the letter ever reach your friends house(web server). When your friend gets the letter they will then send a response. This response goes through the exact same process as your letter(packet) does.
Neil Anuskiewicz
11,007 PointsThat's a reasonable metaphor. It's interesting, DNS is fundamentally important yet few people (including myself) truly understand it. It's like magic. :-)
Jason Anders
Treehouse Moderator 145,858 PointsThanks Brandon. I like that analogy. :)
Frances Collins
1,610 PointsSince the process of a DNS server in use is intangible, I wonder if a biology metaphor would be another good way to explain it, since those processes are intangible too. People take a lot of Biology in high school and college. I can't remember enough of it right now to make that metaphor, but it would be an interesting one.
Neil Anuskiewicz
11,007 PointsFrances, I think specifically an ecology metaphor would work well. There's the sort of gaia that the root domain servers control and bioms under that. I think it would work but someone would have to break it down so it makes sense. Better yet, forget metaphors, we're Treehouse students, maybe a web app that explains DNS with a simple visual presentation. :-)
Neil Anuskiewicz
11,007 PointsDNS is so mission critical that most companies have two DNS servers, a primary and a secondary server. Many have even more just in case. It's that important. If your DNS isn't working, NOTHING is working: web, email, etc.
Example, take a look at how many name servers Treehouse has: http://www.whois.com/whois/teamtreehouse.com
Neil Anuskiewicz
11,007 PointsNeil Anuskiewicz
11,007 PointsWell said, Jason. With no DNS everything on the Internet would have impossible to remember numbers, instead of user friendly names (e.g., teamtreehouse.com). Without DNS you'd go here to get to Team Treehouse's Website: http://173.247.98.20 and writing them an email would be equally delightful.
Neil Anuskiewicz
11,007 PointsNeil Anuskiewicz
11,007 PointsBTW, Jason, I didn't mean to say that Treehouse had their own in house DNS servers. I saw that they have a hosting company and the servers are well distributed it looks like. I do need to be more precise in my writing though.
It's funny, I once wrote an article on DNS for the Linux Journal. I think it's a useful very basic synopsis: http://www.linuxjournal.com/article/4597
Jason Anders
Treehouse Moderator 145,858 PointsJason Anders
Treehouse Moderator 145,858 PointsSorry Neil.
I misunderstood what you were saying. By the way. That was a really well written article. :)
Neil Anuskiewicz
11,007 PointsNeil Anuskiewicz
11,007 PointsThanks for the kind words on my writing. I see from your profile that you're a professional writer. Very cool! What sort of material do you write?
Frances Collins
1,610 PointsFrances Collins
1,610 PointsSo the DNS is the "post office," which a third party is (Company X) as hired by Company Y who is the content developer (ex: the company that is Treehouse). So is there a Company Z that keeps up the servers with the website content stored, or does Treehouse, for instance, do this under their own roof?
Jason Anders
Treehouse Moderator 145,858 PointsJason Anders
Treehouse Moderator 145,858 PointsHey Neil.
I haven't actually written in awhile... I've been working on coding studies. I used to do general interest and music reviews. You can read some of my past works on my site.
:)
Anthony Tantillo
1,009 PointsAnthony Tantillo
1,009 PointsI was struggling to understand this concept. That explanation was very helpful.