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DNS information

By d247
Jan 27, 2011
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  1. Hi ppl

    i would like to find out more obout dns and networking so is the ne place where i can get free info or free e books on the subject thanks ppl
     
  2. JMMD

    JMMD TechSpot Chancellor Posts: 854

    The information itself is all over the internet, just Google whatever subject you're interested in.
    You can try this site for books or more information:

    http://www.freetechbooks.com/
     
  3. LookinAround

    LookinAround Ex Tech Spotter Posts: 6,491   +183

    Google is your friend ;) Search what is dns and you should find many free good resources. I'd start with Wikipedia and looks like Indiana University has a primer for its students that i'll guess cover the basics.

    in any case, skim through all the search hits
     
  4. jobeard

    jobeard TS Ambassador Posts: 9,318   +618

    very basic concepts are:


    From the very bottom of the data flow (ie from your computer outward)

    Your system needs an IP address (analogous to your home has a street address).
    That IP address is most frequently acquired by a
    Dynamic Host Configuration Protocol (DHCP) request on your Network Adaptor with an active driver.
    That results in settings on your system like
    Code:
            Physical Address. . . . . . . . . : aa-bb-cc-dd-ee-ff
            Dhcp Enabled. . . . . . . . . . . : Yes
            Autoconfiguration Enabled . . . . : Yes
            IP Address. . . . . . . . . . . . : 192.168.0.4
            Subnet Mask . . . . . . . . . . . : 255.255.255.0
            Default Gateway . . . . . . . . . : 192.168.0.1
            DHCP Server . . . . . . . . . . . : 192.168.0.1
            DNS Servers . . . . . . . . . . . : 209.18.47.61
                                                   209.18.47.62
    
    The DHCP request is broadcast and the first DHCP server that can respond will provide the above.
    Here's what's important:

    Gateway: the IP address to which all data flows to exit this system.
    IP address: is my systems location on this subnet (meaning everything attached to the gateway)
    Mask: is a technical detail in the hardware operation of reading address.​

    All Internet traffic is from one IPaddress to another.
    If systemA wants to talk to systemB, the sequence (technical details omitted for simplicity) is like
    • systemA opens a connection to systemB
    • systemB accepts or rejects the connection
    • if accepted, systemB acknowledges that with a short message which is defined by something known as a protocol
      (a well defined and agreed sequence of events and data flows). For example, talking to a webserver, the acknowledgment is
      "HTTP/1.0 200 OK"
    Notice: one IPaddress to another - - good golly Batman, I don't know IP addresses for any website - - how do I find the right one?

    That's the job if the Domain Name System (DNS).
    If a browser wants to access google.com, it needs google's IPaddress, so it asks DNS where is www.google.com.
    Where does it sent that question - - to the DNS Server address give to the DHCP request above. So it asks

    where is www,google.com
    and the reply is one of google's ip addresses
    Having that IPaddress, the browser can then access the site using the open shown above
    and use the HTTP or HTTPS protocols to talk to the server.
     
  5. d247

    d247 TS Rookie Topic Starter

    dns info

    Thank you for your reply to my thread about dns protocol it has helped me to understand it bit better. now wot i would like to know is how to set up a smalll network consiting of 4 computer with onboard rj45 connectors.

    Thanks
     
  6. jobeard

    jobeard TS Ambassador Posts: 9,318   +618

    Code:
    network consiting of 4 computer with onboard rj45 connectors
    hmm;

    do you need Internet access for
    1. just one
    2. none
    3. all
     
  7. d247

    d247 TS Rookie Topic Starter

    hi there i need all 4 to have internet access aswell as a 4 computer network
     
  8. jobeard

    jobeard TS Ambassador Posts: 9,318   +618

    OK, the physical wiring is like
    Code:
    modem===router---- up to four wired systems
                  |
                  + - - - - - plus several wireless (if the router supports it)
    
    When making changes to a router, ONLY use a wired connection.

    Each make/model has a default user/password and a default router address - -

    cite your make/model#

    Unless you've altered your TCP settings on one or more of the PCs, they will all
    connect to the router and easily get Internet service.

    How to verify PC connection to the router:
    get a command prompt
    enter ipconfig /all
    you should see data like
    Physical Address. . . . . . . . . : AA-BB-CC-DD-EE-FF
    Dhcp Enabled. . . . . . . . . . . : Yes
    Autoconfiguration Enabled . . . . : Yes
    IP Address. . . . . . . . . . . . : 192.168.0.4
    Subnet Mask . . . . . . . . . . . : 255.255.255.0
    Default Gateway . . . . . . . . . : 192.168.0.1
    DHCP Server . . . . . . . . . . . : 192.168.0.1
    DNS Servers . . . . . . . . . . . : 209.18.47.61​
    the IP address is given to this PC
    the Gateway should be YOUR router
    and the DNS servers will give you IP addresses for email & browser requests

    Now verify you get timing data for these
    ping 127.0.0.1

    ping {whatever-ipaddress-is-shown} aka ping 192.168.0.4 in my case

    ping 66.102.7.99 <<this is google.com
    now get the DNS to resolve a name using:

    ping google.com​
    one here, your email & browser (on this system) will work correctly.

    Solve the above and then we'll get to sharing between your other PCs ...
     
  9. d247

    d247 TS Rookie Topic Starter

    ok thats all fine there wots next
     
  10. jobeard

    jobeard TS Ambassador Posts: 9,318   +618

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