What is an IP?
The abbreviation “IP” stands for "Internet Protocol". Like many other protocols –such as HTTP, HTTPS, TCP and UDP– it is used to control most communications between various devices, such as computers, telephones, routers, Smart TVs, tablets, digital clocks, and even household appliances. For this a public and/or private network is always used.
What is an IP address?
An IP address is made up of four blocks of numbers. Each number block can range from 0 to 255, and is always separated by a period. It usually appears like this: 192.168.0.130, for a private address; or 184.108.40.206, for a public one.
The IP address assigned to a device on a public or private network is unique and cannot be duplicated. In the event of a duplicated private IP, it would be impossible for these devices to communicate with third parties.
Differences between public and private IPs
A public IP is an address assigned by your Internet access supplier, which, as we mentioned earlier, is unique and unrepeatable throughout the world.
That is, it is just like a telephone number, unique and unrepeatable anywhere in the world.
Just as the supplier assigns this IP to us, it also assigns an IP to the servers that provide us with services, such as Web servers, mail servers, streaming, etc.
A private IP is an internal network, with different IP addresses; if connected to the Internet, all the devices connected to the router of the company supplying the data share the same public IP. In this way it is like a telephone number and a switchboard.
A public IP is like a phone number, and the "switchboard" (the router) assigns private IP addresses. When data is requested, the "switchboard" must convey the information properly to the private IP that is requesting or issuing it.
Public IP of router 220.127.116.11> Private IP of PC1: 192.168.0.10, Private IP of PC2: 192.168.0.11, Private IP of TV 192.168.0.12, etc.>
When do you need to know what your IP is?
It is essential to know what your public IP is when you install a Web server, an FTP server, an e-mail server, games, etc. on your PC.
Differences between a static and dynamic address
A static IP address is an address that never changes; the provider always maintains it over time. A dynamic address is different: each time we restart our Internet connection the supplier changes the IP address assigned to us. The supplier also periodically changes the IP address even if we do not restart our router.
Some fibre optics companies featuring routers with dynamic addresses can see can go up to a year without changing IP addresses, even if the devices are reset. However, if a router is shut off for too long – for example, an hour or more– we run the risk of its IP changing.
As we said before, this is the only the case with some fibre optics companies, since most of them periodically change routers’ IPs; not to mention ADSL lines, whose IPs change constantly.
In the next section we will go into the reason for these constant IP changes by Internet providers.
Differences between an IPv4 and an IPv6
Ipv4 was introduced in 1983 and is, to date, the most widely used protocol worldwide. However, years ago the number of IPv4 addresses ran out, for reasons that we will explain later.
ISPs no longer offer static IP addresses, as, if they did, it would be impossible to assign all users a different IP. When we turn off a router, the connection is freed up. Hundreds of thousands of addresses are permanently disconnected, allowing suppliers to remedy the lack of IPv4 addresses with those that become available in this way.
The cause for IPv4 address limitation is none other than its configuration: as this is a 32-bit protocol, its number is limited to 2 to the 32nd power. You just have to multiply 256 * 256 * 256 * 256 to get 4,294,967,296 addresses as the result.
IPv6 was created to solve the problem of the number of available IP addresses, and improve the data transmission protocol. It consists of eight hexadecimal groups separated by a colon, rather than the period used by IPv4. This means that each device connected to the Internet using IPv6 has at its disposal 2 to the 64th power, or 18,446,744,073,709,551,616 IP addresses.
The use of IPv6 addresses is now widespread, but IPv4 refuses to die, and to this day continues to be the predominant protocol. The use of the promising and solid IPv6 protocol is, however, gradually overtaking the outmoded IPv4.
Sample IPv4 address: 18.104.22.168
Sample IPv6 address: 2607: f0d0: 4545: 3: 200: f8ff: fe21: 67cf
Are an IP address and a MAC the same thing?
An IP address, whether static or dynamic, is provided by an Internet Service Provider; or in the case of a private connection, the one freely assigned by us. A MAC address is like a person's personal identification document, featuring a unique and unrepeatable serial number. Thus, while IPs can change freely, MAC addresses are practically impossible to change – although there are some hackers capable of doing this.
MAC addresses are used, for example, to allow access to a network by a specific and unique MAC number (for example, that of a network card) regardless of the IP it uses.
What IP do I need to open a port on a router?
For certain games on a PC you must open ports on it and on your router. With consoles, this port must be opened on the router provided by the company. In both cases, the traffic from a certain port has to be redirected to the private IP of the device in question.
If, for example, you use a Web server on your PC, by default the assigned port is 80. Therefore, on the router you have to assign port 80 to the IP address of the PC where you have installed the Web server. If you also have other services running on said PC, you have to open ports and redirect them as described in the case of a Web server.
But this last topic calls for a more comprehensive article.