ESDS Knowledge Base


Frequently Asked Questions About IP (Internet Protocol)

What is IP?

IP is the Internet Protocol.

A protocol is nothing more than the definition of the set of rules and codes used by computers to communicate over a network. In the Internet Protocol, one of these rules says that each must be identified unequivocally, through a number, which also takes its name from IP. There can be no more than one computer using the same IP across the Internet, which allows to route the data to the correct destination.

You can make an analogy between the number (or address) and IP address, in the real world and physical address of a house. Thus, IP can also be compared to the set of traffic rules, signs and maps that would allow someone to reach that location.

What is IPv6?

IPv6 stands for Internet Protocol version 6.

You could say that a protocol is a set of rules that enable (enables) communication between devices. Roughly, the protocol is a “language”. The Internet Protocol, or IP, is designed to allow communication between different computer networks and now in its fourth version is the foundation of the Internet.

IPv6 is the successor to IPv4 . It was developed over the last decade for this purpose. Today it is a mature protocol with several advantages over IPv4, and supported by major equipment and computer programs.

Its Internet deployment is already underway and should be accelerated in the coming years. The protocol should already be widespread until 2012, when it is planned to further depletion of IPv4 addresses.

Why IPv6 is needed?

An important feature of the Internet Protocol is that each device connected to the network must have a unique identifier, which is usually called an IP address or IP number. On the Internet, these numbers are centrally controlled, and responsible entity (and the entity responsible for that ) is the IANA (Internet Assigned Numbers Authority).

IPv6 is needed because the free IPv4 addresses are running out. Forecasts indicate that they IANA will be exhausted in about 2012. The IANA redistributes the numbers to regional entities, which in turn do the same for national, or designate them directly to end users.

In IPv6 the amount of available addresses is much greater than in IPv4. These addresses will no longer then be a critical resource, they will be available in abundance. This will allow continued growth of the Internet.

Why IPv4 is running out?

The Internet was not designed to be what it is today. In 1983, it was a predominantly academic network with little more than 100 computers connected. Their success, fueled the growth of Ipv4 exponentially. By 1993 commercial use of the internet began and the current distribution policy of IP addresses was thought because they could run out in two or three years.

The IPv4 address space is not small. Each address is a number with 32 bits, which means there are 4,294,967,296 addresses, but the initial policy of distribution of these addresses was not very appropriate, dividing them into classes. There were three classes of addresses:

  • A Class: Consisted of address blocks 128, each about 16 millions.
  • B Class: Consisted of 16,000 blocks, each having 64 000 addresses, approximately.
  • C Class: Consisted of 2 million blocks, each with 256 addresses.

A Class, for instance, by addressing only the 128 institutions, alone consumed half of the available resources. That was a big waste! Several institutions such as IBM, MIT, HP, Apple, ESDS, among others, received this type of block to use. The other classes did not adequately represent the needs of networks connected to the Internet, being too big or too small.

This political class was responsible for a large waste of resources, in the early days of the Internet, and this is one of the reasons why the new IP addresses are ending. It was, however, modified in 1993 with the adoption of CIDR (Classless Inter-Domain Routing).

Despite the adoption of CIDR and other factors have lessened the demand for new addresses, this demand remains strong. The Internet continues to grow exponentially, with the connection of new businesses, institutions and individuals to the network. Factors such as digital inclusion and 3G technologies, among many others, contribute to this growth. So the addresses are ending.

Why IPv4 is not over yet?

To perceive the imminent exhaustion of IP numbers, when it was started on the commercial Internet, around in 1993, developing a new generation of Internet protocol. This new generation should be the ultimate solution to the problem and, in fact, this development has resulted in what we know today as IPv6.

The development of a new protocol, however, requires considerable time and resources. So, other technological solutions were also adopted in the short term. These new technologies, named below, allowed the reduction of demand for new addresses, and rationalization in how they were distributed, thus postponing their exhaustion.

Among the relevant technologies (that) may be mentioned:

CIDR (Classless Inter Domain Routing) is the routing without the use of classes, described by RFC 1519. With CIDR scheme was abolished in classes, allowing you to assign blocks of addresses with arbitrary size, as needed. CIDR allowed a more rational use of available addresses. Furthermore, CIDR also allowed the aggregation of information in the routing tables, which grew excessively, another contributing factor to enable the continued growth of the network.

Private addresses: RFC 1918 private address specified, not valid on the Internet, which could be used, for example, in corporate networks.
NAT (Network Address Translation): NAT enabled network, using private addresses, from connecting to the Internet. With NAT, just a valid address on the Internet, to connect to a limited extent, an entire institution.

This solution is widely used, however, NAT has a number of problems: it ends with the operating model in order to stop ( peer to peer ), causing complications or preventing the operation of a variety of applications such as voice over IP applications based on SIP, it does not scale well, because it requires heavy processing, it does not work with IPsec, it functions as a stateful firewall, giving a false sense of security to many network administrators and contributing to the failure to adopt good security practices within firms, among others.

DHCP (Dynamic Host Configuration Protocol): Described by RFC 2131, this protocol allows dynamic allocation of IP addresses, which brought the possibility to reuse providers Internet addresses provided to its customers for non-permanent connections, such as those made through dial-up lines or ADSL.

When the IPv4 will end?

Current predictions indicate that the stock of the IANA will end till the end of 2012. The end of the stock may occur at different times in each region.

You may also come under the networks with specific needs that cannot be met even though their  IPs would be in stock. For example, if a network requires a large contiguous block of IP: this may not be available even when there are still smaller blocks in stock. In fact, the distribution policies of the remaining IPv4 addresses are also discussed. As the policies, the end date may be a little early or delayed.

What will happen when the IPv4 is over?

IPv6 has been successfully deployed on the Internet and is being widely used, it will allow the continues growth to the network, and there will be no problems.

Is the Internet going to end?

The end of the IPv4 on Internet will not stop or even crash (The end of IPv4 will not cause the internet to stop or even crash). It is expected that there will be a decrease in growth rate of the network and some new applications that could be created. Perhaps the Internet connections will be more expensive.

With the deployment of IPv6 before IPv4 there is end of problems. Instead, IPv6 brings improvements over IPv4, which should make possible the creation of new applications on the network.

How many addresses exist in the IPv4 Internet addresses? What changes with IPv6?

The addresses in IPv4 are represented internally in computers with 32-bit numbers . That means there are a total of 4,294,967,296 addresses. Some of these addresses are not actually available, because they have special uses. This is the case of the block of addresses reserved for multicasting (a special type of routing packets used in some applications), or the blocks reserved for private addresses.

In IPv6, addresses are represented by 128 bit numbers.

That means there are 340,282,366,920,938,463,463,374,607,431,768,211,456 addresses , which represents about 79 trillion trillion times the available space in IPv4. This number equates to about 5.6 x 10 ^ 28 (5.6 times 10 to 28) IP addresses to be human, or approximately 66,557,079,334,886,694,389 addresses per square centimeter on the surface of the Earth .

Half of the 128 bits, however, is reserved for addresses on the same local network. This means that only 18,446,744,073,709,551,616 networks are different.

The large number of addresses is able to meet the needs of the Internet in the future can be imaginable. It also facilitates the process of allocation of numbers within the network allowing, for example, the automatic configuration of IP addresses based on the physical address of network adapters.

How many IPv4 addresses still available?

Also available are 39 blocks “/ 8” . Each / 8 block represents about 16 million addresses. 39 blocks are approximately 654 million addresses , or 15% of total space .

This may seem a lot, but, according to the NRO ( Number Resource Organization ) only in 2007, 12/8 blocks were used, and the utilization rate has been increasing year by year .

Migration or deployment?

There is talk of deployment of IPv6, and not migration.

The technical term used for the new situation of the Internet and networking in general is dual-stack. IPv6 and IPv4 will certainly work together for a few years, perhaps for many, before IPv4 is disabled.

IPv6 creates a new Internet? Separated from the first?

The “Internet IPv6” is coming from the “IPv4 Internet.” That is, the same computer that is now visible and accessible only through the “Internet IPv4”, once you have access to IPv6, will also be on “Internet IPv6”. So even though technically they are two separate address spaces, the Internet is one. The networks that make up today’s “IPv4 Internet” are those that form the “Internet IPv4 + IPv6”, and in the future, “IPv6 Internet.”

IPv6 does not divide the Internet into two.

What happened to the IPv5?

The number 5 to the protocols of the Internet layer (layer 3) was assigned to the ST ( Stream Protocol ). To better understand the issue, it is necessary to have a history of the Internet:

In the early days of the Internet in the 1970s, when the first versions of IP were created for the NSFnet network (the National Science Foundation U.S.), they actually were part of the TCP. TCP and IP were a single protocol. Today they have different features: IP handles the addressing and routing of data packets from one computer to another, while TCP ensures that the data arrives without error, and reach the correct application on your computer. At the end of the 1970s involved engineers realized that there were many tasks for a single protocol and decided to separate them. Thus, in September 1981, IP has been standardized in RFC 791, along with TCP in RFC 793. This version of IP was standardized by the IETF, but it was the fourth version of the protocol, then got the number 4.

The Stream Protocol is the protocol whose version number is 5. It is not compatible with the IP, except just the version field, which consists of the first bits of information of the data packet as it is also designed for use on networks or the Internet. Its function would be to send voice and video over the network as an alternative to IP. The ST also began to be developed in the 1970s, but the first time that has been standardized by the IETF with RFC 1819 in 1979. It came to be used commercially, but today is no longer in use. Some of the concepts of the protocol, however, are used in MPLS.

The IPng ( Internet Protocol New Generation ), which resulted in the development of IPv6, proposed several protocols. Among them the CATNIP ( RFC in 1707 ), PIP ( RFC 1,622 ) and TUBA ( RFC in 1347 ), which also received version numbers. The SIPP ( 1710th RFC ) was the proposal that became the IPv6 ( RFC 2460 ).

Questions Of Home Users

IPv6 makes access to websites slower?

If you do not have native IPv6 (provided directly by your ISP) and your service provider does not create automatic tunnels to give connectivity, in a few cases this can actually happen.


To create a tunnel, your computer looks for a public server on the Internet, called relay. Your computer will always look for the closest server, but servers can not be next to each other! If the nearest server is in another country, for example, you may notice some slowness in accessing a website via IPv6.

If your ISP offers native IPv6 connections, or you create a possibility to tunnel IPv6 through it, this problem no longer occurs.

How do I install IPv6 on my computer?

If you use Windows Vista, Linux, or Mac OS X, IPv6 is enabled by default.

If you use Windows XP, type ipv6 install at the command prompt.

You can also manually create tunnels of IPv6 through tunnel brokers.

Will I have to replace or upgrade computer programs to get IPv6?

Probably not. The hardware of your computer does not change, and the most modern operating systems like Windows XP, Windows Vista, MacOS X, FreeBSD and Linux already support IPv6.

If your computer only supports older operating systems like Windows 98, it may be necessary to change or upgrade, or installation of an alternative operating system like Linux or FreeBSD.

You may have problems with some software, which still might not work with IPv6 in their current versions … Some of them should be upgraded, others, perhaps, have to be replaced by alternatives.

Does my computer support IPv6?

The hardware of your computer instead, supports IPv6. You will not have to replace any internal components for your computer to work with IPv6. It may be necessary, however, to change the modem, if you use an ADSL or Cable.

As for the software :

If you use Windows Vista, Windows XP, Windows 2000, FreeBSD, MacOS X or Linux, yes.
If you use DOS, Windows 95 or Windows 98, you do not have to change the operating system.

Is IPv6 more secure than IPv4?

By itself, no. But it is interesting to note two things:

With the absurd amount of IPv6 addresses, it will be virtually impossible for someone malicious software/script to scan networks, looking for active addresses. Scans are like serial search … The attacker trying will search/ping addresses, for example: …, until one of them responds. Once there is a reply from a address, it can attempt to invade, or attack. With IPv6 other methods must be used to find out which IPs are active and can be attacked.

As there is no NAT in IPv6, called IPsec Security Extension works well. IPSec is little used in practice today because it does not work with NAT, and can provide, even more security in the use of the Internet.

Will I have to change my ADSL modem / Cable to get Ipv6?

Yes, probably. Most ADSL modems / cables installed today do not support IPv6.

Your provider can offer, while the exchange is made, some mechanism of tunnel broker for IPv6 addresses that you receive through an IPv4 tunnel, without the need to change equipments.

What do I gain with IPv6?

The Internet working, growing and evolving.

Valid IP addresses and fixed in sufficient quantity to use in computers and other devices.

Will I have to pay more for IPv6?

No. Providers will provide addresses and IPv6 along with IPv4, without charging more for it.

Which services work exclusively with IPv6?

There are some unique services. Most of them are still more proof of concept than a real service, but there are interesting proposals, such as IRC servers, Dedicated Servers, Internet News, Torrents, among others, exclusive for those who already use IPv6.

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