What are IP numbers and how do they work?
For a long time, now it is available to the mass public. Luckily there is no source of knowledge.
Basically, this network is based on sending datagrams. A datagram is a "package" of data that starts from one computer to another. Each datagram contains, in addition to the data to send, and other things, the information of both the address of the issuer and the receiver, in a similar way to what we write in the envelope of a conventional letter of mail.
But how can you define the direction of a computer?
Any PC that is in red has at least one "virtual address", which consists of a number that identifies and differentiates all the other machines in the network, that is, no other PC will have the same number, even when said network includes A the whole planet, as in the case of the internet.
This is an identification number 0 to 255 (each XXX is a number between 0 and 255).
As you imagine, this number is called "IP Number". For a computer to communicate with another person it is essential that the station knows the IP of the recipient.
If we have a PC connected to 2 networks (for example, to the internal network of the office and to the Internet), it has 2 IP numbers, one for the office network.
Then the concept of "Network Interface" arises. A network interface is the element that connects to a PC with a Network. In the example, the two interfaces are the Modem and the Red color plate. Therefore, it is not every moment.
Our Internet provider can have X IP numbers, which are the users that connect through it. When our PC connects to the Internet, it communicates with one of the provider's modems and receives the IP that it will use during that call.
In summary, every time we connect to the internet we assign one of the IP numbers available in our provider, that is why our IP is different in each call. This is called "Dynamic IP".
The opposite of Dynamic IP, is logically, the fixed IP. This is the case of computers that are directly connected to the Internet by a network card.
What are DNS?
A website is a set of documents that are stored on a computer (a server). This server has an IP number, which our PC must know in order to order the HTML files and images (in other words, the pages).
How can I see a website if I do not know the IP number of the computer on which it is hosted?
There is a service on the Internet called "Domain Name Service" or "Domain Name Service" (DNS), which consists of putting a "friendly" name to each IP address, to allow you to remember easily.
For example, the Yahoo page, our computer automatically requests a DNS server that translates "www.yahoo.com" (the domain name) to its IP number (which is 216.32.74.52) and then we can then communicate with the site.
In a DNS server, there is a large "database" where each domain has its corresponding IP number. And any PC in the network can consult it. (in fact it does it automatically every time we visit a site)
Can I get a domain for my website? (DNS limitations)
As we said, a DNS server has an equivalent IP number for each domain. Therefore, to have a domain of our own, it is necessary that our page be hosted on a computer with a fixed IP. Since otherwise, the DNS server could never determine its IP number (because it would vary every time).
That is why it is not possible for normal Internet telephone users to have a domain of their own.
Beware, it should not be confused with the concept of "self-control" with the concept of own page. It is possible to have your own page on the internet, which actually consists of hosting our documents in a subdirectory within a free server. (Like Geocities or Xoom)
