What does it mean if a public IP address looks like a private IP address?

For example, I go to 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.

1 Answer

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).