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Real & Private IP Address

By k4k ·
what factor makes a IP Address as Real & Private IP Address. in other words what stops you from using private Ip Address like 192.168.1.1 as real IP ?

given 64.37.102.20 & 192.168.1.5 just by looking at the IP Address how can i say which is real ip & which is Private IP ??

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Real & Private IP Address

by NetTek In reply to Real & Private IP Address

The routers on the Internet are specifically programmed not to route private addresses. That means that any traffic from a private LAN that uses private IP addresses will never get past the first Internet router it comes to.

The following rangesof IP addresses are reserved for private use. They will never be issued for use on the Internet.
10.0.0.0 through 10.255.255.255
172.16.0.0 through 172.31.255.255
192.168.0.0 through 192.168.255.255

Therefore, 64.37.102.20 is public, and 192.168.1.5 is private.

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Real & Private IP Address

by k4k In reply to Real & Private IP Address

does this means i can use 173.16.64.55 as real IP

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Real & Private IP Address

by isys In reply to Real & Private IP Address

Read RFC 1**8 here:

http://www.cis.ohio-state.edu/cgi-bin/rfc/rfc1**8.html

Basically, they are not Internet routable.

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Real & Private IP Address

by k4k In reply to Real & Private IP Address

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Real & Private IP Address

by krautner In reply to Real & Private IP Address

Hi,

The previous two answers were pretty right. But I thought I'd add a bit more just to ensure you've been answered correctly.

Due to the problem with finite IP addresses running short, IANA (Internet Assigned Numbers Authority) defined a range of IP addresses in each IP class used, eg, Classes A, B and C, to be designated as private IP ranges and therefore and devices on public networks will not route anything from these ranges.

If one has a private IP, they will need to have a device NAT any messages from the Private IP to a public IP on the same device.

The following list shows the range of IP's assigned as private IP ranges and as are defined in RFC1**8.

Class A Private IP’s: 10.0.0.0–10.255.255.255
ClassB Private IP’s: 172.16.0.0–172.31.255.255
Class C Private IP’s: 192.168.0.0–192.168.255.255

Having said that however, if one is using NAT on the a router with a public IP on one side, then you can actually use a given public range on the internal network bearing in mind that if you do so and you wish to actually get to a real IP address on the outside world that is in the same range you are using on your internal network, you are not likely to do so.

Regards

Bob Krautner
DSL Provisioning Team Manager
Data Configuration Group

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Real & Private IP Address

by k4k In reply to Real & Private IP Address

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by k4k In reply to Real & Private IP Address

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