Nat Addressing & RDP question

DerekAustin26DerekAustin26 Member Posts: 275
in CCNA & CCENT
We all know that NAT Addressing is what allows our IP's to be private.
Because of this we dont waste millions of public ip's.

So because of this, this means It is possible I could have the same IP as someone else.

So with that said, if I was to remote into your computer after you gave me your IP, I can.

But how is that possible if I have the same IP as you or if you have the same IP as someone else?
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Comments

  • tierstentiersten Member Posts: 4,505
    NAT/PAT converts internal private addresses to a single public address. People can have their own internal set of addresses. You can't access somebody elses internal addresses without some forwarding mechanism in the NAT/PAT device.
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  • networker050184networker050184 Mod Posts: 11,962 Mod
    If you were going to remote into my PC would I give you my private or public address?
    An expert is a man who has made all the mistakes which can be made.
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  • DerekAustin26DerekAustin26 Member Posts: 275
    networker050184 wrote: »
    If you were going to remote into my PC would I give you my private or public address?

    Well you'd give me your private ip. which is just your ip.
    Whenever anyone gives out their IP, their giving out their private ip, unless their not behind NAT.
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  • networker050184networker050184 Mod Posts: 11,962 Mod
    If I gave you my private IP there would be no way you could reach my computer routing over the internet.

    I would give you my public IP which would be forwarded to my private by the NAT device. When it got to my private it would have your public as the source, not your private.

    I think you need a little more reading on NAT. You don't seem to be understanding correctly.
    An expert is a man who has made all the mistakes which can be made.
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  • DerekAustin26DerekAustin26 Member Posts: 275
    yeah, that makes sense. But see, what if there were other pc's on your local network, how would you giving me your public direct me to your specific pc?
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  • tierstentiersten Member Posts: 4,505
    DerekAustin26 wrote: »
    yeah, that makes sense. But see, what if there were other pc's on your local network, how would you giving me your public direct me to your specific pc?
    You'd configure multiple port forwarding rules on the gateway.
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  • networker050184networker050184 Mod Posts: 11,962 Mod
    What he said.
    An expert is a man who has made all the mistakes which can be made.
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  • DerekAustin26DerekAustin26 Member Posts: 275
    tiersten wrote: »
    You'd configure multiple port forwarding rules on the gateway.

    But what if i didnt configure anything on my router and it's already doing it? I'm connected directly to my modem provided by my ISP. My bro wants to connect to me, all he does is enter in the IP i gave him and bam, he's connected to me. There is another computer using the same network in this house wirelessly.

    So back to the original question, how is he getting to my pc with just my ip when I never gave him my public ip or made configurations on my router?
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  • networker050184networker050184 Mod Posts: 11,962 Mod
    The modem just send all traffic destined to it for the inside address by default.

    On your brothers side it works a little different since the connection is outbound.

    What IP address are you giving him?
    An expert is a man who has made all the mistakes which can be made.
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  • phoeneousphoeneous Member Posts: 2,333 ■■■■■■■□□□
    DerekAustin26 wrote: »
    But what if i didnt configure anything on my router and it's already doing it? I'm connected directly to my modem provided by my ISP. My bro wants to connect to me, all he does is enter in the IP i gave him and bam, he's connected to me. There is another computer using the same network in this house wirelessly.

    So back to the original question, how is he getting to my pc with just my ip when I never gave him my public ip or made configurations on my router?

    If you are in a house with 24 rooms under one roof, you don't need to go outside to go from room to room.

    If you tell him what room you are in, and as long as the door isnt locked and he knows how to get to that room then he can just walk right in. He doesnt need to know your public street address because he is already there.
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  • tierstentiersten Member Posts: 4,505
    DerekAustin26 wrote: »
    But what if i didnt configure anything on my router and it's already doing it? I'm connected directly to my modem provided by my ISP. My bro wants to connect to me, all he does is enter in the IP i gave him and bam, he's connected to me. There is another computer using the same network in this house wirelessly.
    How is the wireless connected?

    Is it:
    Internet <---> Modem <---> YourPC <--Wireless--> OtherPC
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  • DerekAustin26DerekAustin26 Member Posts: 275
    networker050184 wrote: »
    the modem just send all traffic destined to it for the inside address by default.

    On your brothers side it works a little different since the connection is outbound.

    What ip address are you giving him?

    192.168.2.2
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  • tierstentiersten Member Posts: 4,505
    DerekAustin26 wrote: »
    192.168.2.2
    That is a private non routeable IP address. Unless you're doing something like IPSEC then that won't work. He's either using another IP or there is something else going on.
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  • DerekAustin26DerekAustin26 Member Posts: 275
    tiersten wrote: »
    How is the wireless connected?

    Is it:
    Internet <---> Modem <---> YourPC <--Wireless--> OtherPC

    Internet -- Modem -- WAP -- PC or Wireless PC
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  • Bl8ckr0uterBl8ckr0uter Inactive Imported Users Posts: 5,031 ■■■■■■■■□□
    DerekAustin26 wrote: »
    192.168.2.2

    You aren't using any vpn or anything?

    That is the way it works for me at work. I connect to the vpn > I connect to my work machines private ip using rdp and it works. Are you guys using anything like that?
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  • networker050184networker050184 Mod Posts: 11,962 Mod
    Like tiersten said it doesn't work that way. You are both either on the same LAN or have a tunnel set up.
    An expert is a man who has made all the mistakes which can be made.
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  • DerekAustin26DerekAustin26 Member Posts: 275
    no, I'm going over to his house and he's gonna show me some stuff. I'll have to get back to you guys on this.. I may be a little confused. too be continued... Thanks though guys
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  • hodgey87hodgey87 Member Posts: 232
    DerekAustin26 wrote: »
    We all know that NAT Addressing is what allows our IP's to be private.
    Because of this we dont waste millions of public ip's.

    So because of this, this means It is possible I could have the same IP as someone else.

    So with that said, if I was to remote into your computer after you gave me your IP, I can.

    But how is that possible if I have the same IP as you or if you have the same IP as someone else?

    Im just going to jump in an give my pennies worth :)

    NAT is used to help with the lack of ipv4 addresses, it is more than likely that you have the same private ip address as someone else, but these private ip addresses never leave the lan as they are not routable.

    This is where the public ip address comes in, this ip address is unique to a company for example. If you are looking at RDP within a lan then you can just simply do that type in the private address that you are attempting to connect to and it will work.

    However if you require an RDP over to another network i.e. a different company, you need to create a VPN connection to that network via the public ip addresses. With this connection established you are able to connect to any ip address even if its the same as yours.

    Thats the way i see it, i may be totally wrong ;)
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  • phoeneousphoeneous Member Posts: 2,333 ■■■■■■■□□□
    hodgey87 wrote: »
    However if you require an RDP over to another network i.e. a different company, you need to create a VPN connection to that network via the public ip addresses. With this connection established you are able to connect to any ip address even if its the same as yours.

    Thats the way i see it, i may be totally wrong ;)

    Unless the public is NAT'ed, like terminal servers, then there is no need for a vpn.
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