net+ newbie question regarding whatismyip.com

Hi all.
I'm sure you're all familiar with the site, whatismyip.com. My question is when I use that site to check my ip, it's different thatn when I use the cmd line utility, "ipconfig" on my widows box. I must have a concept error here. The dos window shows, "192...blah, blah", but the website shows "75...blah".
I do have a router that I'm on. Any reason why they dont match up?

Thanks,

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Comments

Beibo

Hello, I believe it is because the Ip that whatismyip.com shows is a public Ip Adress and the one you see in your computer is your internal ip address that your router gave you.

ratbuddy

I only spent a few moments googling for you, but What is Network Address Translation (NAT)? seems to have some decent info. Network Address Translation is what you need to read about if you want to understand why you see two different IP addresses.

jvrlopez

Whatismyip.com = Public IP

Ipconfig = Private IP

In a nutshell, NAT takes your internal private IP and translates it to a public IP that can be routed through the Internet.

This is done to conserve IPv4 addresses since they're limited. Basically, private IP ranges are available to be used for whatever purpose. However, should you need to connect with a different network via the Internet, your private IP needs to be changed to a public (unique) address so it may be routed correctly.

deep_logic

Thanks for the reply's guys. I'm still reading the net+ book and I don't know if he metions the public vs. private IP address.

RouteMyPacket

deep_logic wrote: »

Thanks for the reply's guys. I'm still reading the net+ book and I don't know if he metions the public vs. private IP address.

No clue what Net+ entails but as others said, it is due to NAT. This is what is used to translate private IP's or "RFC1918" addresses to Public IP (Outside Global).

You will eventually get into more detail along the Cisco tracks when it comes to NAT/PAT and Inside Local, Inside Global, Outside Local and Outside Global addresses.

Keep it up, you are on your way.

j.petrov

jvrlopez wrote: »

Whatismyip.com = Public IP

Ipconfig = Private IP

In a nutshell, NAT takes your internal private IP and translates it to a public IP that can be routed through the Internet.

This is done to conserve IPv4 addresses since they're limited. Basically, private IP ranges are available to be used for whatever purpose. However, should you need to connect with a different network via the Internet, your private IP needs to be changed to a public (unique) address so it may be routed correctly.

Its most definitely covered in Net+.