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White and gray IP addresses, what is it?

A brief reference guide on external and local (white / gray) IP addresses – why they are called that way and where they come from.

This article may be useful in the following cases:

Game server or web server does not start

The torrent client reports that there are no incoming connections (green is off)

The forums recommend opening ports, setting up a firewall and antivirus

The following concepts are used in this article:

Subscriber – a person who uses the services of a provider.

Client – a person or software that uses the Internet.

Internet server / service – software for the provision of services on the Internet.

The following notation is used in the diagrams:

Green lines – “Internet cable” with white IP.

Red lines – “Internet cable” with gray IP.

1. White address.

Scheme number 1

The computer of each subscriber is connected to the equipment of the provider without intermediaries. With this scheme, all computers have direct access to the Internet and white IP addresses. The subscriber can run any Internet servers / services on his computer. For example, you can connect a computer to a domain and run a website on it for free, and at the same time there will be much more opportunities than any paid hosting. You can also start your own mail server, FTP server, game servers and much more.

But even with this scheme, the provider can limit the use of connectivity options and the subscriber can only be a client: use sites, download files, play network games, and other client programs.

2. Absolutely gray address (for NAT provider).

Scheme No. 2

In the diagram, green stripes are “wires” on which there is a white address, red – gray.

With this scheme, several subscribers go online on a single wire. This is called accessing the Internet through a local network. With this scheme, the subscriber is located behind the NAT provider. Subscribers have gray local addresses, the provider’s router has a white external IP. All subscribers have different internal addresses and one external address for all. This connection scheme is used by providers in order to connect many subscribers to one channel. The speed usually depends on the activity of subscribers, sometimes even in the tariff plan not fixed speed is indicated, for example, up to X or from X to XX. For low-quality providers, it often happens that with high activity of subscribers, no subscriber gets normal Internet.

With this scheme, subscribers can only be a client: use sites, download files, play network games. You cannot start any Internet service on your computer.

Gray Address Ranges:

10. 0. 0. 0 – 10. 255.255.255
172. 16. 0. 0 – 172. 31.255.255
192.168. 0. 0 –

Even with this connection scheme, not everything is lost. For example, the subscriber may ask the provider to redirect the ports that the service running on the subscriber’s computer will use.

3. Your NAT. The address is white but you do not use it.

Scheme No. 3

In this diagram, routers belong to subscribers.

With this scheme, all the subscriber’s computers are connected to a local network and all have access to the Internet.

Despite the fact that computer addresses are in the gray ranges, they are no longer gray, as the subscriber has full access to the router and can configure port forwarding.

There are situations when a subscriber, not knowing why this is necessary, connects one computer through a router although it is not needed. Some models of ADSL modems by default operate in router mode and subscribers without going into details connect in this mode and you get one computer on the local network with an already not completely gray address.

As in Scheme 1, a subscriber can run any Internet services on any computer on the local network: connect the computer to the domain and run the site on it for free, while there will be much more possibilities than any paid hosting. You can also start your own mail server, FTP server, game servers and much more. The difference is only in the settings of the router.

The provider may also make restrictions on the use of the channel.
Ways to organize a local network with providing one computer with an external white address

The drawback of Scheme # 3 is that not all servers and services can work with ports forwarded through NAT. For example, the game servers of some games on ADSL modems in router mode do not want to be added to the master list. But without a router, only one computer can be connected to the Internet. And, in general, it is very problematic to create a local network without a router.

The router can be configured in two modes:

Router – Scheme №3

Bridge – Schemes 4 and 5

We put the router into Bridge mode.

On the computer that will be the server:

Windows XP: Control Panel >> Network.

Windows 7 Vista: Control Panel >> Network and Sharing Center.

Create a new connection >> Enter the username / password issued by the provider >> Start this connection.

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