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Setting up NAT with Packet Tracer 5

wbosherwbosher Member Posts: 422
in CCNA & CCENT
I'm trying to set up NAT using Packet Tracer. Is there some way of setting up an "internet" so that it will not except private ip addresses? icon_confused.gif
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    networker050184networker050184 Mod Posts: 11,962 Mod
    I've never used packet tracer, but why don't you just NAT to another private address if it won't let you NAT to a public address?
    An expert is a man who has made all the mistakes which can be made.
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    wbosherwbosher Member Posts: 422
    The problem is that I have set up a whole bunch of routers with public address using a EIGRP so simulate the internet. I have also created a small LAN using private addresses. I can ping any of the public routers from my private LAN which I wouldn't be able to do in the real world without NAT. I want to be able to simulate the real world somehow by not being able to ping the public routers without NAT. I haven't set up NAT yet so I shouldn't be able to ping these routers.

    Packet Tracer has a frame relay "cloud", I was wondering is there is an internet "cloud" or something similar.

    Hope this makes sense to someone.
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    networker050184networker050184 Mod Posts: 11,962 Mod
    Don't advertise the private addresses into your routing protocol.
    An expert is a man who has made all the mistakes which can be made.
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    wbosherwbosher Member Posts: 422
    But if I did that, them my LAN router (default gateway) wouldn't be able to ping the public routers at all because it wouldn't know about them.
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    networker050184networker050184 Mod Posts: 11,962 Mod
    As long as your LAN routers outside interface has a public address that is advertised it would be able to reach the rest of the "internet." Its just like in the real world, you would only advertise your public addresses into the internet not your private.
    An expert is a man who has made all the mistakes which can be made.
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    wbosherwbosher Member Posts: 422
    This brings up another problem. All the public routers can see each other and my LAN routers outside interface, but not the inside LAN addresses. That's fine, but in order for my inside devices to access the internet I have set up a default route. They quite happily ping all the other other routers where in the real world the ISP would stop that from happening without NAT. Packet Tracer doesn't appear to have an ISP. icon_wink.gif
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    networker050184networker050184 Mod Posts: 11,962 Mod
    If the other routers did not have a route to your private addresses then you would not be able to ping. You need to look at the source address in the ICMP packets. It would be impossible to ping (to get a response) if the destination does not have a route back.
    An expert is a man who has made all the mistakes which can be made.
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    wbosherwbosher Member Posts: 422
    D'oh!!! I have realised that I used this lab previously in my CCENT studies and set up static routes all over the place which I forgot to remove. icon_redface.gif
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