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For example, I go to http://whatismyipaddress.com/ and it tells me that my IP address is 192.X.Y.Z. What does this mean? Isn't that a private IP address? How can I find my real public IP address?

EDIT: It may be worth mentioning that I am behind a corporate firewall/proxy.

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  • It may be the proxy injecting your/its IP into the headers. What is your LAN address? What is the Proxy's address? If you try google.ca/search?q=what+is+my+ip or whatismyip.com does it provide the same IP? Dec 16, 2014 at 19:17
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    Only 192.168.x.y is a private address. Anything else that starts with 192 may be a public address.
    – pooter03
    Dec 16, 2014 at 19:20

1 Answer 1

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There are several ranges of 'private' ip addresses, as defined in RFC1918. These are:

 10.0.0.0        -   10.255.255.255  (10/8 prefix)
 172.16.0.0      -   172.31.255.255  (172.16/12 prefix)
 192.168.0.0     -   192.168.255.255 (192.168/16 prefix)

That an IP address starts with 192 doesn't necessarily mean it's a private IP address. For example the ISP Surfnet in The Netherlands assigns IP addresses starting with 192.87, which are perfectly valid Internet addresses (see RIPE Whois database).

Only when an IP address is in the ranges above, it's a private IP address and shouldn't be routed onto the internet (and a lot of ISP's block these ranges).

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    Of course, IP meaning Internet Protocol, those are valid Internet addresses. And they are routed onto the Internet. They're just not public IP addresses, and are not to be routed onto the public Internet. Aug 13, 2017 at 18:23
  • @JürgenA.Erhard you are totally right my friend. It's too bad this answer went 2,5 years without your comment, I'm sure people will be much better informed now.
    – mtak
    Aug 14, 2017 at 6:48

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