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end-to-end break and NAT

Discussion in 'Networks' started by kobem, Apr 7, 2008.

  1. kobem

    kobem Megabyte Poster

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    hey i am sorry again but i have been thinking something for about 2 years. And it was end-to-end
    thing.

    for example i am using MSN Messenger, i want to transmit a file via MSN Messenger to my friend
    at his house who uses MSN Messenger. However, there is NAT implemented on my modem.This
    will change my IP address(source) by matching it with the public address as you know.

    And NAT is told to break the end-to-end rule. How can this become?
    since just source IP address changes not the ports at the transport layer.


    2- About this end-to-end rule again. let's consider the MSN Messenger. Even NAT is applied
    on my modem, packets reach the destination(my friend) somehow. So what is the disadvantage
    about NAT?
     
    Certifications: CCNA
  2. BosonMichael
    Highly Decorated Member Award

    BosonMichael Yottabyte Poster

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    WIP: Just about everything!
  3. kobem

    kobem Megabyte Poster

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    hey i just have 2 months to deliver my thesis. I know IP is connectionless and do not make
    end-to-end, just send the packets.

    see that from wikipedia

    "End-to-end connectivity is a property of the Internet that allows all nodes of the network to send packets to all other nodes of the network, without requiring intermediate network elements to further interpret them."


    but even if you think IP, the intermediate devices(routers) exist between end nodes. And
    these will break end-to-end.
    .............
    I'm trying to say is that even if you do not implement NAT but you have routers between end nodes,
    end -to-end rule gets broken , am i wrong?
    ....................
     
    Certifications: CCNA
  4. BosonMichael
    Highly Decorated Member Award

    BosonMichael Yottabyte Poster

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    No, not really.
     
    Certifications: CISSP, MCSE+I, MCSE: Security, MCSE: Messaging, MCDST, MCDBA, MCTS, OCP, CCNP, CCDP, CCNA Security, CCNA Voice, CNE, SCSA, Security+, Linux+, Server+, Network+, A+
    WIP: Just about everything!
  5. Bluerinse
    Honorary Member

    Bluerinse Exabyte Poster

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    You are correct Kobem..

    Source..

    http://en.wikipedia.org/wiki/Network_address_translation
     
    Certifications: C&G Electronics - MCSA (W2K) MCSE (W2K)
  6. kobem

    kobem Megabyte Poster

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    the thing i am trying to tell is that, TCP is not fully performed. If you make use of NAT or
    not , you can't apply end-to-end.

    so why do we blame for NAT ? what is the difference if everytime some intermediate
    devices exist among end nodes?
     
    Certifications: CCNA
  7. kobem

    kobem Megabyte Poster

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    he please reply
     
    Certifications: CCNA
  8. hbroomhall

    hbroomhall Petabyte Poster Gold Member

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    I'm afraid I'm baffled as to quite what the question is.

    The article that Bluerinse points to is a very good discussion of the pros and cons.

    Harry.
     
    Certifications: ECDL A+ Network+ i-Net+
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  9. kobem

    kobem Megabyte Poster

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    i read that article.

    i want to express this: even if you do not implement NAT,there are always routers among end nodes.
    In Internet environment you never clinch one end to other end. (intermediary devices exist all time)
    NAT is told to break down some mechanisms such as mobile IP,IPSec since NAT changes
    source address of internal device(end node).

    even if you do run NAT, do source and destination ports change ?
     
    Certifications: CCNA
  10. hbroomhall

    hbroomhall Petabyte Poster Gold Member

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    NAT often implies PAT - as that article mentions.

    Harry.
     
    Certifications: ECDL A+ Network+ i-Net+
    WIP: Server+
  11. kobem

    kobem Megabyte Poster

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    PAT yes.. i forgot it. many-to-one mapping by using ports.
     
    Certifications: CCNA

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