50 Comments

  1. saikiran goud on June 17, 2021 at 7:34 pm

    well explained



  2. Ben Nelson on June 17, 2021 at 7:34 pm

    Thank you for teaching so well!



  3. RamGopal K .S on June 17, 2021 at 7:35 pm

    Thanks for posting such a good video.



  4. A Pall on June 17, 2021 at 7:37 pm

    I was desperate for a simple DNS Resolution answer like that!



  5. NAB420 on June 17, 2021 at 7:37 pm

    Excellent job…Can I know which software you are using for drawing that flow please?



  6. Mahesh Yadav on June 17, 2021 at 7:38 pm

    thanks, was really helpful



  7. Miri Babayev on June 17, 2021 at 7:38 pm

    Just OMG, couldn’t be explained easier. WELL DONE, like + sub!



  8. Govind Rai on June 17, 2021 at 7:39 pm

    Thank you, Barry, for contributing your knowledge. Super helpful.



  9. redona kajmaku on June 17, 2021 at 7:40 pm

    You say that you are going to cover up the reverse lookup in another video. I am not able to find it. Is it uploaded? I would really appreciate it. Your videos are really helpful and make it so easy to grasp the concepts. Thank you!



  10. Shweb98 on June 17, 2021 at 7:41 pm

    Much appreciated



  11. Chris Hutchins on June 17, 2021 at 7:42 pm

    So question: if another client sends a query for another .com domain (www.youtube.com for example) and the ISP recursive server at 10.5.1.8 does not have the resolved IP address cached, does it at least cache the root zone’s response to reach the .com nameserver at c.gtld-servers.net at 198.41.0.4, and thus, forward the query straight to .com zone instead of asking again from the root zone?



  12. asds92 on June 17, 2021 at 7:45 pm

    I’ve been in IT for over 20 years. I assumed I knew how DNS actually worked until this video. It’s so clear that I almost feel STUPID! Thanks for this



  13. Scott Hanley on June 17, 2021 at 7:46 pm

    Superb tutorial, many thanks for uploading. Looking forward to future videos (Y)



  14. ZerOv7 on June 17, 2021 at 7:46 pm

    This series was very well explained and straight to the point. I wish that you publish more videos about DNS and networking. Thanks a lot for this quality content.



  15. i3igmind on June 17, 2021 at 7:47 pm

    Simply Amazing explanation. I love the way you presented this material. how simple and straight to the point. Good job man! please do more vids. Quick question, which application are you using for your white boarding ? Thanks



  16. Brian Wilson on June 17, 2021 at 7:49 pm

    Barry – these concepts are very well explained, very much like khan academy. Similar style too. Hope to see more!



  17. Paulo Bazuka on June 17, 2021 at 7:50 pm

    Great content. Thank you for sharing it.



  18. Trance Prince on June 17, 2021 at 7:50 pm

    thank you great video!



  19. Elegantic on June 17, 2021 at 7:51 pm

    Its not a virus? Right?



  20. D Thakuri on June 17, 2021 at 7:52 pm

    Hi,
    I found this explanation awesome. I understood the RECURSIVE QUERY but could you please explain the AUTHORITATIVE and NON-AUTHORITATIVE ANSWER in this example?
    Thanks you!



  21. J on June 17, 2021 at 7:53 pm

    Amazing video! More videos please!



  22. Elias Zeray on June 17, 2021 at 7:54 pm

    simple and detail. Thank u.



  23. Jose Cobo on June 17, 2021 at 7:54 pm

    Best explanation Ever!



  24. Nver Khachoyan on June 17, 2021 at 7:57 pm

    I want more videos! Thank you.



  25. Brodie Robson on June 17, 2021 at 7:58 pm

    Watched all your vids for DNS, as Im studying networking.. brilliant work



  26. Anupam Maurya on June 17, 2021 at 7:59 pm

    Amazing



  27. Dinky Digital on June 17, 2021 at 7:59 pm

    Excellent video



  28. Rajeshwari .p on June 17, 2021 at 8:00 pm

    how do the zone file in ISP looks like … Whether there will be A record / NS record ??? just please explain the same.. Ex : how the ISP find the root IP address ?



  29. superthommy on June 17, 2021 at 8:00 pm

    Isn’t this an iterated query?

    The different DNS-servers sends the response ( i dont know, ask this server ) back to the ISP, instead of asking the lower level DNS-server directly.



  30. Prakash Selvaraj on June 17, 2021 at 8:00 pm

    neatly explained



  31. Darren Ng on June 17, 2021 at 8:03 pm

    Hi Barry, the example you have given is NOT a recursive query. A recursive query puts burden of name resolution on the contacted name server, with heavy load at the upper levels of hierarchy. eg. HOST -> LOCAL DNS -> ROOT -> TLD -> AUTH DNS -> IP (reverse). The example you have given is iterative where the (ROOT, TLD, AUTH) replies with names of server to contact.



  32. Joan Roig on June 17, 2021 at 8:06 pm

    Really good explanation



  33. Ess Jay on June 17, 2021 at 8:08 pm

    Thanks for this brilliant video on DNS Resolution. It helped me clear my doubts significantly. But I still have one doubt ie what if, considering this example only, yahoo changes its server IP address. Will local ISP resolve it still from cached data, and if not how will it get to know that IP is changed for Yahoo.
    Appreciate your thoughts on it.



  34. Sahil Rally on June 17, 2021 at 8:10 pm

    Great series, thanks , unfortunately everyone stops at this exact spot. I am looking for further like following
    1. Linux commands to see . Probably any visual tool.
    2. How to configure DNS server on local computer.



  35. Ayedun Jossy Oladipupo on June 17, 2021 at 8:10 pm

    Very detailed and simple explanation.. Thanks so much for this… I appreciate you



  36. Amit Kumar on June 17, 2021 at 8:10 pm

    Yahoo.com must be running on some port, right? How does the host computer know which port the application is running on?



  37. Farseen CK on June 17, 2021 at 8:11 pm

    Hi, could you explain the different types of DNS queries – NS, A, etc?



  38. Nekrozys on June 17, 2021 at 8:11 pm

    Isn’t it more like:
    Recursive: Do you know the IP of http://www.yahoo.com ?
    Root: No but .com might know. (NS)
    Recursive: Ok, then do you know the IP of .com ?
    Root: Yes, it’s X.X.X.X (A)

    instead of:
    Recursive: Do you know the IP of http://www.yahoo.com ?
    Root: No but .com might know AND its IP is X.X.X.X (NS + A in one request ?) ?



  39. m0nk 0 on June 17, 2021 at 8:15 pm

    Awesome video, thanks a lot. Thats simple and to the point… Waiting for more videos !!! thanks again



  40. Rajiv Kumar on June 17, 2021 at 8:19 pm

    had seen this video and forgot the mechanism. Back here after same question was asked in an interview and I didn’t answer. Poor me 🙁



  41. DavP98 on June 17, 2021 at 8:20 pm

    Hi Barry, great explanation, but i’d like to point out that what you call a top level domain server is actually a Root Nameserver. Top level domains are for instance .com, .org, etc.



  42. Julian on June 17, 2021 at 8:23 pm

    great explanation thx!



  43. kalahasthi vasu on June 17, 2021 at 8:23 pm

    a very nice explanation sir



  44. Murali S on June 17, 2021 at 8:24 pm

    great explanation.. very easily explained. why did you stop making further videos on DNS?



  45. Kenny T Mule Jnr on June 17, 2021 at 8:24 pm

    As simple as that… Excellent bro



  46. Airbus Driver on June 17, 2021 at 8:26 pm

    Why are university professors so bad at teaching anything? I’ve found 99% of the material on YouTube to be way better and understandable rather than some overpaid plonker at university. Thanks, Barry!



  47. Subhasree Mukherjee on June 17, 2021 at 8:27 pm

    very nice explanation Sir!



  48. The Coding Journal on June 17, 2021 at 8:28 pm

    Thank you barry



  49. Tresten Pool on June 17, 2021 at 8:28 pm

    Awesome little series!!! Thank you very much



  50. Murtaza kalabhai on June 17, 2021 at 8:34 pm

    Loving explanation and mind blowing…………………………..