DNS recursive query vs. Iterative query

The goal of DNS is to resolve a fully qualified domain name (FQDN) to an IP address. The process is called name resolution.
In this video I will use one example to demonstrate the whole process how name resolution is done. At the same time, the difference between recursive query and iterative query is explained.
Please leave comments, questions and
Please subscribe to my channel
Many thanks,
Sunny Classroom

[@brandonhunter3036]

I always forget the difference between “iterative” DNS query types and “recursive” DNS query types, but this video was a very helpful refresher.

[@sunnyclassroom24]

thanks.

[@gaelguedia]

This is what I see when I talk about good tutorial format. Whatever your type of memory you can understand and easily memorize it. Good job thanks

[@sunnyclassroom24]

Many thanks for watching and leaving encouraging comment!

[@memoryhero]

Perfect. Brings tears to the eyes.

[@africanxpress9185]

Absolutely a pleasure to follow and learn from.

[@ukuduck531]

Crystally clear! What an amazing teacher!

[@sunnyclassroom24]

Thanks a lot.

[@joneslt]

Agreed! People who understand technology are a dime a dozen. People who can clearly explain it like this is extremely rare

[@ZuhaibMohammed]

Thank you. I am preparing for an interview and the explanation was perfect.

[@sunnyclassroom24]

good luck to you.

[@amitshirazi5285]

IM SO THANKFUL FOR GODS INCREDIBLE DECISION TO GIVE BIRTH TO A GENIOUS AND AMAZING PERSON LIKE YOU sunny you are my sunshine thank you for these perfect videos im addicted

[@sunnyclassroom24]

Thank you very much, Amit!

[@eliasbotte1203]

I love you Sunny, you are literally better than all my teachers combined. College is a bruh moment

[@Thxiz]

Thank you very much Sunny! I was unsure how recursive query vs. Iterative query worked, but now I do!

[@satyapramod8762]

Great Explanation on DNS. I clearly understand recursive and Iterative query.

[@kapztcs]

Perfect explanation on what I was looking for....

[@FitnessAesthetics]

Thankyou so much..I am clear now with these concepts.. love From India..

[@PeterOdhiamboAbwoga]

A clear explanation of DNS queries. thank you, sir

[@advaitnikesh8221]

Can’t explain better than this 👍🏿

[@fahada783]

Fabulous technically way of teaching.

[@egemenklc2515]

Simply perfect, thank you so much for your work sir.

[@lesptichats]

You're amazing Sunny!! Thank you so much for explaining things so clearly

[@sunnyclassroom24]

You're so welcome!

[@amitrathod1134]

much helpful thankyou sir, keep uploading videos

[@sunnyclassroom24]

Thanks a lot. I will do.

[@mohammadsediqi6961]

thank you for explaining in very simple way with the very clear example, i really like the way you teaching.

[@sunnyclassroom24]

Glad to hear that!

[@smfarhan2754]

Excellent description about DNS. Thank you

[@ranjanrohit64]

just awe=some and nice explanation and very crisp and clear. Thanks a lot.

[@sunnyclassroom24]

thanks a lot!

[@gunelaliyeva_19_85]

That was an amazing explanation. Thanks

[@srikanthkumar6227]

Well explanation...impressive lesson

[@sunnyclassroom24]

Thanks! 😃

[@janecat31121]

thanks you make it soooo clear in a simple way, never stop.

[@sunnyclassroom24]

You are welcome and thanks a lot for your words.

[@theworldisyours2241]

teaching is an art ..

[@ppvshenoy]

Thank you for the clarity presented between recursive and iterative. Much appreciated.

[@sunnyclassroom24]

You are welcome!

[@eduardotrindadedasilva113]

exact what I needed to understand in a matter of minutes. Thank you a lot for the video

[@sunnyclassroom24]

You are welcome!

[@a.r.mohapatra3391]

Beautifully explained except one Big Mistake, you've Altered the Definition. Iterative query is between a DNS Client and its local DNS Server. Recursive Query is between Local DNS and Other DNS.

[@RalphFarah-r1q]

you have no idea how easy you made that

[@kapiljoshi1491]

Thank u 🙏 for such type of explanation.

[@thisnyper]

Very nice video, extremely helpful. Thank you very much Sunny

[@sunnyclassroom24]

You are welcome! Many thanks for watching and leaving nice comment.

[@tiffanywallace9373]

Perfect, as usual. Thanks Sunny.

[@dadaverdiyev4098]

great and easy

[@arsenruslanovich6642]

Best source to learn thank you

[@harshithaniranjan5057]

Awesom perfect explanation

[@runrunsomethings5229]

Awsome Sunny. Very brief but detailed

[@sunnyclassroom24]

Thank you very much!

[@penemanhati927]

Very good explaination and clarity in pronouncation

[@sunnyclassroom24]

thanks for your compliment. I appreciate it very much.

[@MohammedSalemDMC3]

Welcome back Sunny...
thank you for your hard work

[@sunnyclassroom24]

You are welcome and many thanks for your words, which mean a lot to me.

[@mohamedshlibik6190]

amazing clarification, well done Sunny

[@rounakjaiswal4216]

Very good explanation .

[@aswina646]

Really helpful and easy to understand.....Thanks a lot for the effort you took. :-)

[@sunnyclassroom24]

You are welcome!

[@timshoemaker9023]

Hello, sunnyclassroom! Nice upload. You are a good teacher. I hope you continue to upload more videos. Any topics would be great! Yours sincerely fan.

[@africanxpress9185]

Absolutely a pleasure to follow and learn from. Bravo!

[@fernandavln38]

Good explanation.

[@VijayKumar-id9vy]

Thank you for making this Video. It was simple to understand.

[@tiruinternationalpublicspe4932]

Awesome Explanation Sunny , You just stole my Heart .

[@nusratnoor443]

Awesome video bro India 🇮🇳

[@sunnyclassroom24]

Thank you!

[@harshtayade]

Why always ,I am late on such quality content channel...

[@venkataswaroop6686]

Nice explanation 👍👍

[@xinong01]

I have learned a lot from your channel. I hope you will keep on doing these great lessons.

[@sunnyclassroom24]

will do. Thanks a lot for your comment and the time to write your comment.

[@bhanjansarma8196]

very helpful, It's clear my doubt.........post more more networking concepts

[@tusharu9107]

Very clear explanation , really very helpful

[@progamamedia6946]

Super

[@extramild1]

Thanks you sir, very helpful

[@sunnyclassroom24]

Thank you very much for your kind comment. Happy 2019 Year!

[@sofiavelazquez5616]

Excellent information! It’s very clear

[@CosmicBeams]

Too good Sunny! Thank you 🙏🏼

[@SoldierNr.1]

Good Video, thanks

[@sunnyclassroom24]

You're welcome

[@elvisw3001]

I like your information!!

[@seshuganeshlosetti5515]

Very clear sir... Thanks

[@sunnyclassroom24]

You're most welcome

[@azizxon3405]

Thank you, perfect explanation!

[@sunnyclassroom24]

You are welcome!

[@qdpl8]

You are Namber 1! thank you

[@sunnyclassroom24]

You are welcome. Thank you very much!

[@stephenmartin5201]

Excellent!

[@sunnyclassroom24]

I appreciate.

[@HunainJan-rb8ju]

Very good nice

[@lijuanye1349]

Very easy to understand, thanks a lot!!!!!

[@sunnyclassroom24]

You are welcome!

[@deepakkprajapati2417]

Hey @sunny Classroom, not sure if you still respond to query. Just a question what is Authortative and Non-Authortative query ?

[@deckertone]

Very helpful!! Thanks :)

[@sunnyclassroom24]

You're welcome!

[@shreyashdhasade9717]

Quality lecture! Thank you so much sir

[@mrshiv3166]

Hi Sunny, very clear and concise video. Quick question,the initial root domain name lookup is done by the router of the ISP on behalf of the local router isnt it?

[@mikaelljung5063]

Only if you use the ISP´s caching dns as a forwarder. If you are using root hints (which is the default) everything happens exactly as Sunny told you. It could be faster to use the caching server of the isp (or another caching dns provider like 8.8.8.8) as a forwarder

[@billyffa]

Mr. Sunny, you da man!

[@islamicvideos352]

Pro level teacher

[@marcdimarc1]

Thanks for the video Sunny

[@sunnyclassroom24]

You are welcome evolution!

[@90K1D]

Thank you for this god sent explanation.

[@barorome497]

thanks for the explanation

[@kool1311]

refer to Iterative flow 4:40.
What does the root server reply back to local dns server?
I understand that root server reply NS record and A record of dot com server.
Please guide me if I misunderstand.

[@GrandxxGxx]

an excellent explanation

[@sunnyclassroom24]

Thanks.

[@vivekprajapati7911]

thanks sir you are new hope in my learning.....

[@mrg3921]

Very helpful!

[@TheRealOne744]

Sunny you are a god!

[@aditikhedkar8514]

You're amazing dude!

[@DuyTran-ss4lu]

Best

[@sunnyclassroom24]

thanks!

[@hariharamoorthythennetipan2190]

Simply superb....

[@mrjango8948]

Extremely Great Content Bro 👍👍👌

[@Dennis-Hu]

thank you for the help
easy to understand

[@sunnyclassroom24]

you are welcome!

[@egor.okhterov]

So, does every device in the world makes requests to the root DNS? Doesn't it DDOS that machine?

[@jonhatanbecerra9997]

Amazing explanation!

[@sunnyclassroom24]

thanks a lot!

[@captainAOG]

Amazing very amazing example ❤️

[@sunnyclassroom24]

Thank you for watching! check out my other videos please!

[@santhuraj26]

GREAT VIDEO BRO.

[@sunnyclassroom24]

Thank you very much, bro.

[@jarves1231]

Hi, where does DNS forwarders come in? Say my workstations primary local dns is localDNS1 and localDNS1 has a forwarder set to localDNS2 and localDNS2 has a forwarder set to a public DNS. So the flow would become like this client -> localDNS1 -> localDNS2 -> publicDNS. Would the recursive DNS server be localDNS2 and localDNS1?

[@faizanali-gr8yx]

that was awesommmmmmmmeeeeeeeeeeeeeeeee.

[@sunnyclassroom24]

Thanks a lotttttttttttttttttttttttt

[@thedynasty2679]

Thank You 🙏🏽

[@yujianzhao6461]

In the last slide, it says "When this local DNS server could not resolve a new name from its own database, it would make an iterative query to other DNS servers". Is "database" correct? I thought according to the video, it should be "When this local DNS server could not resolve a new name from its own CACHE, it would make an iterative query to other DNS servers". Please help clarify, thanks!

[@koolganja]

I believe ‘database’ and ‘cache’ both can be used to describe the DNS Resolver’s cache.

[@yujianzhao6461]

@@koolganja You mean "database" actually refers to "cache"?

[@sirorco1]

Thank you !

[@TheLabbening]

Thank you

[@Felix2011y]

Awesome explanation as always , but got a question: what if I configured my DNS server to be Google's DNS, because I don´t have a local DNS server, how will the queries process occur? Thanks in advance!

[@mikaelljung5063]

If you means googles caching dns (8,8,8,8) it works exactly in the same way as with the local dns server. Just keep in mind that 8.8.8.8 is not the same dns server as dns.google.com. dns.google.com is the authoratative dns server for the hosts in the google.com domain. It can only resolve hosts like ftp.google.com, or subdomains like support.google.com. If you want to resolve a name like google.se it will not be able to resolve it.

[@leksetengah]

is local dns server = ISP?

[@shaharblank98]

What is the default?

[@lyubomirnikov1636]

nice one

[@prashanth9285-]

Easy peasy.

[@bintehawa7712]

❤❤❤❤❤❤ from Pakistan

[@jannatulferdous450]

Thanks!!

[@sunnyclassroom24]

You are welcome!

[@RahulChauhan-ow7mj]

Hello Sir,
Please create one video for DNS Forwarding and Conditional Forwarding.
Thanks
Rahul Singh

[@sunnyclassroom24]

I put it on my to-do list. I promise to do it.

[@RahulChauhan-ow7mj]

Sunny Classroom thank you so much sir