Initial Connection

DerekAustin26DerekAustin26 Member Posts: 275
in CCNA & CCENT
When your pc makes its VERY first connection to a device/pc/server etc.. - What is taking place here? Before the source can send data to the destination and vica verca.. The source has to have a path laid out. But when the routers have never seen the "friendly name" of the end user, how does it go about getting resolved so that the source can eventually send to the destination/end user? (And this destination is not on the same LAN as you) Example: someone on the other side of the world.

Obviously once a connection has been established the source can just view the received packet and respond back to the source. But keep in my my question is about the very first connection that takes place in order for the Session to exist.


Incase your still curious what im getting at:
Example #2:
You wanna send a message to "George" (friendly name of destination) - This packet is received by the router and broadcasted to the DNS Server -(Since DNS Server has NEVER seen this destination before) How does George get resolved to the IP Address that YOU are trying to send to?
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Comments

  • dynamikdynamik Banned Posts: 12,312 ■■■■■■■■■□
    It depends on how the DNS server is configured.

    If it can only respond to entries in its local database, it will be unable to return an answer if it doesn't have an entry for that.

    If it is configured to forward queries to another DNS server (perhaps its ISP's servers), it will forward the query to that server and let that server try to answer from its local database or perform recursion.

    If it is configured to use recursion, it will go through a hierarchy of DNS servers to find an entry.

    For example, if you're trying to resolve microsoft.com for the first time, the DNS server will first query the root (.) server to find a DNS server that is authoritative for the "com" TLD, then it will query that server to find which server is authoratative for the "microsoft" domain, and then it will query that server to get the actual IP address of the host.
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  • kalebkspkalebksp Member Posts: 1,033 ■■■■■□□□□□
    DerekAustin26 wrote: »
    Example #2:
    You wanna send a message to "George" (friendly name of destination) - This packet is received by the router and broadcasted to the DNS Server -(Since DNS Server has NEVER seen this destination before) How does George get resolved to the IP Address that YOU are trying to send to?

    Dynamik's explanation of DNS is accurate, but I think you may be misunderstanding which device queries the DNS server. When you go to techexams.net for the first time your computer sends a query to it's configured DNS server (which could be manually configured or dynamically via DHCP). The DNS server replies with the IP address of the host, which your computer will then use to communicate with techexams.net. Routers don't really have anything to do with DNS or name resolution.
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  • miller811miller811 Member Posts: 897
    Reading the original post, I am wondering if the OP is really questioning the operation of ARP and not DNS.
    I don't claim to be an expert, but I sure would like to become one someday.

    Quest for 11K pages read in 2011
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  • dynamikdynamik Banned Posts: 12,312 ■■■■■■■■■□
    miller811 wrote: »
    Reading the original post, I am wondering if the OP is really questioning the operation of ARP and not DNS.

    Yea I know. I couldn't really tell, so I just took a stab :D

    You can do ARP ;)
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