Web Hosting Forum Login
Not a member yet? Sign up

DNS Resolution

  • HOME
  • FORUMS
  • BLOGS
  • WEB HOSTING OFFERS
  • ADVERTISING
  • FIND A HOST
  • WEB HOSTING
  • QUICK MENU
  • REGISTER HERE - Join us for FREE
Results 1 to 8 of 8

Thread: DNS Resolution

  1. #1
    Join Date
    Jul 2016
    Location
    Hertfordshire, UK
    Posts
    656
    Thanks
    33
    Thanked 149 Times in 130 Posts
    Thumbs Up/Down
    Received: 292/2
    Given: 113/3

    Post DNS Resolution

    DNS Resolution

    What is DNS ?

    DNS is the domain name system or service it translates the domains and FQDN’s (hostnames) into IP address so the server can be connected to on the network level. Without DNS everyone would need to enter an IP address into the search bar instead of a friendly easy to remember domain name such as ljshost.com.

    So How Does It Work ?

    It’s really quite simple there many servers around the world running a DNS service such as Bind.
    These servers serve DNS information for various domains.

    Resolution Process

    First thing we need to talk about is the holy of holy’s the 13 root name servers, if anything happened to these servers then no more internet for anyone they are the source from where all DNS information comes. The root servers are referenced as a single .

    a.root-servers.net.
    b.root-servers.net.
    c.root-servers.net.
    d.root-servers.net.
    e.root-servers.net.
    f.root-servers.net.
    g.root-servers.net.
    h.root-servers.net.
    i.root-servers.net.
    j.root-servers.net.
    k.root-servers.net.
    l.root-servers.net.
    m.root-servers.net.

    Now we have a starting point we can begin to explain how we get from here to .debian.com. DNS works in reverse which might seem confusing at first but will make perfect sense once you see how we get from the root servers to the next level. When you enter debian.com into your browser the following happens.

    Step 1

    Every computer or internet connected has one or more DNS servers that it is configured to use any attempt to resolve a name will first be asked to this server, if it has the record it will return it to the user and the resolution process is complete, if not this DNS server will ask the root server.

    Step 2

    Using the Linux dig command with a trace is a great example to show how the process works

    dig +trace debian.com

    This command will display the resolution process for debian.com


    The first part of the output shows the root server providing the information for the GLD .com name servers


    . 129258 IN NS f.root-servers.net.
    . 129258 IN NS h.root-servers.net.
    . 129258 IN NS l.root-servers.net.
    . 129258 IN NS a.root-servers.net.
    . 129258 IN NS k.root-servers.net.
    . 129258 IN NS e.root-servers.net.
    . 129258 IN NS d.root-servers.net.
    . 129258 IN NS i.root-servers.net.
    . 129258 IN NS m.root-servers.net.
    . 129258 IN NS j.root-servers.net.
    . 129258 IN NS b.root-servers.net.
    . 129258 IN NS c.root-servers.net.
    . 129258 IN NS g.root-servers.net.





    ;; Received 698 bytes from 192.42.93.30#53(g.gtld-servers.net) in 129 ms

    com. 600 IN NS b.gtld-servers.net.
    com. 600 IN NS k.gtld-servers.net.
    com. 600 IN NS m.gtld-servers.net.
    com. 600 IN NS d.gtld-servers.net.
    com. 600 IN NS i.gtld-servers.net.
    com. 600 IN NS c.gtld-servers.net.
    com. 600 IN NS f.gtld-servers.net.
    com. 600 IN NS e.gtld-servers.net.
    com. 600 IN NS g.gtld-servers.net.
    com. 600 IN NS a.gtld-servers.net.
    com. 600 IN NS j.gtld-servers.net.
    com. 600 IN NS l.gtld-servers.net.
    com. 600 IN NS h.gtld-servers.net.



    Next we can see the GLD server e.gtld-servers.net gave us the name servers for debian.com

    debian.com. 172800 IN NS sec1.rcode0.net.
    debian.com. 172800 IN NS sec2.rcode0.net.
    debian.com. 172800 IN NS dnsnode.debian.org.

    ;; Received 418 bytes from 192.12.94.30#53(e.gtld-servers.net) in 117 ms

    And finally dnsnode.debian.org provided the IP for debian.com

    debian.com. 300 IN A 140.211.15.34
    debian.com. 300 IN A 149.20.20.22
    debian.com. 300 IN A 5.153.231.4
    debian.com. 300 IN A 128.31.0.62
    debian.com. 300 IN A 130.89.148.14

    ;; Received 1179 bytes from 194.146.106.126#53(dnsnode.debian.org) in 49 ms


    As you see, DNS is very simple it’s just like state, city, town, name in the Telephone directory.


    Caching (TTL)

    With the billions of DNS requests made every day this system would quickly become overloaded and fail, to solve this problem each server keep a record of all information it has served for a period of time. Each DNS record has a time limit, when this time has expired that DNS server will discard the record and begin the resolution process again from the root servers. Caching records for a period of 24 hours or more reduces the number of root level requests made to a minimum and reduces overall global DNS load.

    Dig www.google.com

    www.google.com. 235 IN A 216.58.208.164


    Here you can see the name server asked for the www.google.com IP address has the record and it has 235 seconds to live before it is discarded.
    UK Web Hosting | Reseller Hosting | VPS | Domain Registration | Affiliates
    100% Cloud Powered | 30 Day Money Back Guarantee | cPanel | 365 Day UK Support
    https://www.ljshost.com

  2. The Following User Says Thank You to LJSHost For This Useful Post:
    David Beroff (12-17-2016)

  3. #2
    Join Date
    Jul 2016
    Location
    Kochi
    Posts
    62
    Thanks
    4
    Thanked 9 Times in 8 Posts
    Thumbs Up/Down
    Received: 49/0
    Given: 24/0
    Good one !!

  4. #3
    Join Date
    Apr 2016
    Posts
    107
    Thanks
    43
    Thanked 1 Time in 1 Post
    Thumbs Up/Down
    Received: 8/0
    Given: 96/0
    Is Godaddy or Cloudflare using these ways for their DNS services?

    Those techniques are pretty high and I need time to read and study them.

  5. #4
    Join Date
    Jul 2016
    Location
    Hertfordshire, UK
    Posts
    656
    Thanks
    33
    Thanked 149 Times in 130 Posts
    Thumbs Up/Down
    Received: 292/2
    Given: 113/3
    Yes Chris,

    Godaddy and CloudFlare will use this resolution process just like any other internet user or service provider.
    UK Web Hosting | Reseller Hosting | VPS | Domain Registration | Affiliates
    100% Cloud Powered | 30 Day Money Back Guarantee | cPanel | 365 Day UK Support
    https://www.ljshost.com

  6. #5
    Join Date
    Nov 2014
    Posts
    254
    Thanks
    6
    Thanked 19 Times in 15 Posts
    Thumbs Up/Down
    Received: 84/0
    Given: 47/0
    Very easy to understand guide for everyone! Good job.
    Web Hosting - Professional Hosting Solutions
    Web Hosting Forum - Web Hosting Community

  7. #6
    Join Date
    Dec 2016
    Location
    United States
    Posts
    51
    Thanks
    0
    Thanked 2 Times in 2 Posts
    Thumbs Up/Down
    Received: 19/0
    Given: 0/0
    Thank you for the post, defiantly some good information in here!

  8. #7
    Join Date
    Apr 2016
    Posts
    107
    Thanks
    43
    Thanked 1 Time in 1 Post
    Thumbs Up/Down
    Received: 8/0
    Given: 96/0
    Quote Originally Posted by LJSHost View Post
    Yes Chris,

    Godaddy and CloudFlare will use this resolution process just like any other internet user or service provider.
    If Godaddy and CloudFlare are using same resolution process like that, I will wonder why DNS on Cloudflare updates more faster than Godaddy, they could use new technology.

  9. #8
    Join Date
    Jul 2016
    Location
    Hertfordshire, UK
    Posts
    656
    Thanks
    33
    Thanked 149 Times in 130 Posts
    Thumbs Up/Down
    Received: 292/2
    Given: 113/3
    Update: As an addtion to my DNS resolution article I thought I would expand on the topic with whois and Glue records.

    How does DNS work with Whois ?

    As we all know when you have a new domain or change hosting provider on an existing domain, the name servers for the domain must be updated by the domain registrar for that domain.

    To expand on my previous article on how DNS resolution works I thought it would be interesting to discuss where the link between whois name server records and the DNS resolution process is made. Registered DNS operators also maintain the whois database. For example when you type debian.com into your browser the name server you are using will begin the resolution process as explained above starting with the whois server

    Their is one exception to this rule which is the IP Glue record which "Glues" the name servers to the IP address in the whois record.

    Glue Records which are also referred to as custom name servers. Custom nameservers are useful for many different reasons for example a VPS or dedicated server owner might like to have their own name servers to register domains under that they want to host on the server.

    Custom name servers are also essential for resellers as they can register and update their customers domains under their own brand which creates the white labeled hosting that all reseller hosting providers offer.

    Here is how glued and Unglued name servers appear on a whois record

    Without With Glue Record

    Nameserver: ns1.somedomain.com.
    Nameserver: ns2.somedomain.com.

    With Glue Record

    Nameserver: ns1.somedomain.com. xxx.xxx.xxx.xxx
    Nameserver: ns2.somedomain.com. xxx xxx xxx xxx

    As you can see with a Glue record the IP of the correct name servers to ask is included in the whois record, this answer is not authoritative and only acts as a pointer allowing for the loop to be resolved.


    So Why Are Glue records needed ?

    If the name servers for a domain are a subdomain of the domain the resolution process with get stuck in a loop and be unable to resolve. This does sound confusing but it’s quite simple.

    Lets try to visualize what is happening with all these name servers talking to each other and you will see why the glue record is needed.

    1. Nameserver asks the whois server what are name servers for somedomain.com
    2. Whois server - ns1.somedomain.com. ns2.somedomain.com.
    3. Hi root server whats the IP for the .com name server
    4. Hi .com server whats the IP for the somedomain.com name server
    5 .com name servers says ask ns1.somedomain.com
    6. Hi somedomain.com whats the IP for ns1.somedomain.com
    7. Somedomain.com says ask ns1.somedomain.com
    8. Whats the IP for ns1.somedomain.com
    9. Ask ns1.somedomain.com


    Without Glue records this is where we get stuck, the name servers for somedomain.com are a sub domain of somedomain.com so we can’t find out the IP addess to connect with ns1.somedomain.com Once the IP are glued to the whois record the looping problem is solved.
    UK Web Hosting | Reseller Hosting | VPS | Domain Registration | Affiliates
    100% Cloud Powered | 30 Day Money Back Guarantee | cPanel | 365 Day UK Support
    https://www.ljshost.com

Newer Threads

  1. David Beroff
    energizedit
    Replies: 5 | Views: 236
    Last post by energizedit, 12-18-2016, 02:01 AM
  2. Moebuntu
    SenseiSteve
    Replies: 10 | Views: 371
    Last post by SenseiSteve, 12-22-2016, 08:14 PM
  3. marcyslen
    LJSHost
    Replies: 15 | Views: 498
    Last post by LJSHost, 01-14-2017, 01:58 PM
  4. marcyslen
    LJSHost
    Replies: 11 | Views: 411
    Last post by LJSHost, 01-14-2017, 02:52 PM
  5. StartVM
    ferngullygraphics
    Replies: 5 | Views: 390
    Last post by ferngullygraphics, 12-19-2016, 03:16 PM

Older Threads

  1. HostXNow
    hynds
    Replies: 9 | Views: 164
    Last post by hynds, 12-22-2016, 03:51 PM
  2. energizedit
    StartVM
    Replies: 5 | Views: 393
    Last post by StartVM, 12-19-2016, 04:32 AM
  3. energizedit
    HostXNow
    Replies: 4 | Views: 318
    Last post by HostXNow, 12-17-2016, 06:59 PM
  4. energizedit
    HostXNow
    Replies: 4 | Views: 344
    Last post by HostXNow, 12-17-2016, 06:45 PM
  5. HostXNow
    Nixtree
    Replies: 5 | Views: 70
    Last post by Nixtree, 12-17-2016, 05:26 AM

Latest Threads

  1. David Beroff
    David Beroff
    Replies: 0 | Views: 8
    Last post by David Beroff, Today, 02:39 AM
  2. WPCycle
    WPCycle
    Replies: 2 | Views: 35
    Last post by WPCycle, Yesterday, 08:47 PM
  3. steitieh
    Gecko
    Replies: 5 | Views: 47
    Last post by Gecko, Today, 02:17 AM
  4. steitieh
    energizedit
    Replies: 1 | Views: 80
    Last post by energizedit, Yesterday, 02:51 PM
  5. wpspeedster
    wpspeedster
    Replies: 3 | Views: 149
    Last post by wpspeedster, Today, 03:54 AM

Similar Threads

  1. arronmattwills
    arronmattwills
    Replies: 8 | Views: 2149
    Last post by arronmattwills, 05-03-2014, 03:42 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Web Hosting Forum

ForumWeb.Hosting is a web hosting forum where you’ll find in-depth discussions and resources to help you find the best hosting providers for your websites or how to manage your hosting whether you are new or experienced. You’ll find it all here. With topics ranging from web hosting, internet marketing, search engine optimization, social networking, make money online, affiliate marketing as well as hands-on technical support for web design, programming and more. We are a growing community of like-minded people that is keen to help and support each other with ambitions and online endeavors. Learn and grow, make friends and contacts for life.

Community

The world's smartest hosting providers come here to discuss & share what's trending in the web hosting world!
Copyright ©2017, ForumWeb.Hosting. All rights reserved. Web Hosting Forum for webmasters, web hosting providers, designers and web developers.

Welcome to Forum Web Hosting

The World's Number 1 Web Hosting Community, Reviews & Services

Log in!

Continue with Facebook
Continue With Email. By signing up you indicate that you have read and agree to the Terms of Service and Privacy Policy.

Sign in Manually

Need an account? Sign up now!