Question about outside global/local

kadshahkadshah Senior MemberFrom NYC but currently living in ThailandPosts: 385Member ■■■□□□□□□□
I have read the Ciscopress ICND pg 281 Nat addressing terms many times but
am still having trouble understanding where exactly outside global and inside local is.
I made a little diagram so can someone point to which interface is global and which is local?
Is interface s0/0 on kaj outside global or is it outside local? icon_confused.gif

thank,

-k

outside.jpg

Comments

  • forbeslforbesl Posts: 454Member
    kadshah wrote:
    I have read the Ciscopress ICND pg 281 Nat addressing terms many times but
    am still having trouble understanding where exactly outside global and inside local is.
    I made a little diagram so can someone point to which interface is global and which is local?
    Is interface s0/0 on kaj outside global or is it outside local? icon_confused.gif
    Got Cisco?? icon_rolleyes.gif

    http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080094837.shtml
  • kadshahkadshah Senior Member From NYC but currently living in ThailandPosts: 385Member ■■■□□□□□□□
    thanks i will check out the info you gave me. I'm not trying to beat up on you but it would have been nice to hear you explain it in a way that makes sense to you.
    If you think about it every question on this forum could be answered with a link.
    I'm sure you already understand the concept of outside/inside global and could have probably explained it better than cisco :D
  • optimusoptimus Posts: 183Member
    Yeah, you got it right. The ones of the left are inside local and inside global as stated. The ones on the right would be outiside global (for the serial interface), and outside local (for the ethernet interface).

    Basically, the inside ones are YOUR network where you are doing your own NAT translations. Then the network on the right is the network you are communicating too. You are shown that the outside global is whatever their ISP IP address is that they are using, and their outside local is the computer host which has the private IP address more than likely. Wehter or not it is also using NAT I could not tell you, but it doesn't really matter. What matters bigtime is that network on your left, which shows your own computer's private IP (inside local), and the ISP address being used on your router (inside global).

    INSIDE - YOUR NETWORK
    OUTSIDE - SOME OTHER NETWORK YOU ARE COMMUNICATING TOO.


    - Optimus
  • HumperHumper Posts: 647Member
    Ahh I remember the confusion of NAT terms back in the day :D

    If you still need help let me know I will try and post something simple for you to understand...but the above posters have done a good job...

    I think what forbesl is trying to get you to do is your OWN research on the topics instead of coming here for help all the time. I am not saying you do but it happens alot in the CCNA forums (I was probably guilty of this as well last year)....When you start your CCNP certification you really shouldn't come here for help unless you have exhausted all options....
    Now working full time!
  • kadshahkadshah Senior Member From NYC but currently living in ThailandPosts: 385Member ■■■□□□□□□□
    thanks! i needed someone to explain this in the vernacular cause no matter
    how many times i read the ICND it just didn't make sense to me. Now if i could only
    memorize the Nat terms in my head all will be fine. icon_wink.gif
  • Paul BozPaul Boz Posts: 2,621Member
    the best way to remember it for me is to think like this:

    Your network is inside, to you. Your request remains inside YOUR network. When you send a request outbound to another network, you are no longer inside your network, but outside of it, so the remote network is outside. As far as global and local, that's easy. Just remember that global addresses are addresses that are understood by every other network, where as local addresses are known only to your network. Global = globally understood. EVERYONE can route to you via your global addresses. Heck, local is like localhost, IE it's your own network/system.

    Lets assume you want to ping someone on my network here at EATEL.

    1.) Your computer's IP address may be 192.168.7.234.

    2.) When you send out your email request your edge router translates your "local" address to a global address for routing across the WWW to EATEL.

    3.) Your ping request gets here with the IP address of 64.56.125.34, or whatever your assigned global address is. My network doesn't know what your local address is and doesn't care, just so long as it knows to send the ICMP reply to 64.56.125.34. Your router, which is running NAT, will handle the translation to your inside local address once the ICMP reply is sent back.
    CCNP | CCIP | CCDP | CCNA, CCDA
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  • kadshahkadshah Senior Member From NYC but currently living in ThailandPosts: 385Member ■■■□□□□□□□
    Got it!
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