IPv4, which stands for Internet Protocol version 4, is a fundamental technology that enables the transmission of packages through the Internet by providing a unique identifier to each connected device. Developed in the early 1980s, the IPv4 address pool has a theoretical limit of 4.3 billion unique addresses. Nowadays, all IPv4 addresses are either in active use or are reserved for special purposes and cannot be used by the general public. An example IPv4 address would be 192.168.1.1.
Whenever a client machine such as a PC, phone, tablet, or another smart device gets connected to the Internet, it is assigned an IP address. The assigning authority is usually the Internet Service Provider (ISP) which, in turn, is authorized by the local Regional Internet Registry (RIR). The ISP needs to be aware of the IP address of every connected device on their network so that when a remote server responds to the client’s query they can efficiently route all traffic to its intended destination.
IPv4 operates on a best-effort delivery model. This means that packet delivery is not guaranteed. Moreover, packets may be received out of order or the same packet may be delivered more than once. These data integrity issues are resolved by the Transmission Control Protocol (TCP) which is part of the next networking layer, namely the Transport Layer.
To learn even more about what an IPv4 address is and how it differs from IPv6, continue reading or jump to the section that interests you.
- What Is an IP Address?
- Where Are IPv4 Addresses Used?
- Examining the IPv4 Address Structure
- Why Is IPv4 Being Replaced by IPv6?
- Are IPv4 and IPv6 Compatible?
- What Are the Differences Between IPv4 and IPv6?
- Conclusion
What Is an IP Address?
An IP address is a numeric identifier that gets assigned to every device that is connected to the Internet. You can think of the IP address as someone’s phone number – you can successfully communicate with that person only if both you and the person in question have valid phone numbers.
IP addresses are often hard to remember which is why they are commonly substituted for domain names in URLs. In fact, it is recommended that every website owner buys a memorable domain name to make their website easily accessible.
You can learn more about what IP addresses are and how they are used in web hosting in our dedicated article on the subject.
Where Are IPv4 Addresses Used?
IPv4 addresses are used throughout the Internet since they act as the connective tissue that binds all hosts into a world-wide-web. Without IP addresses, you would not be able to connect to the web nor exchange data packets with remote hosts. In fact, during data packet transmission it is common for every packet to make several hops across third-party routers until it reaches its final destination, thus utilizing multiple IPv4 addresses in a single operation.
This method of packet transmission is used for all Internet-based activities such as checking your email, chatting with a friend, streaming movies, playing online games, and, of course, browsing websites. Here at AwardSpace, we use IPv4 addresses across our entire suite of hosting solutions. Our free website hosting package, premium shared hosting plans, and semi-dedicated servers use IPv4 addresses that are shared among several customers. In contrast, our VPS hosting solutions can provide you with your own IPv4 address.
Since IPv4 addresses are not particularly memorable, they are almost always substituted by domain names that act as IPv4 aliases. In fact, domain names have been the norm when it comes to accessing websites for decades.
When your web browser tries to load the homepage of a given domain, it needs to resolve the domain back into the underlying IPv4 address. This is accomplished using the Domain Name System (DNS). DNS servers are organized in a hierarchy and the process of resolving a domain name into an IP address is very similar to looking up a word definition in a dictionary.
Public vs Private IPv4 Addresses
As we have mentioned previously, the IPv4 address pool holds just under 4.3 billion unique IP addresses. Not all of these addresses are available for public use, however. Around 18 million are reserved for use in private networks and another 270 million are reserved as multicast addresses.
Private IP addresses are most often used in home and business settings. In such scenarios, you have a router that can access the Internet directly and also creates a local area network (LAN). Devices that connect to the LAN are assigned private IPs through a DHCP server and are able to communicate with the outside world using a process called network address translation (NAT).
Examining the IPv4 Address Structure
IPv4 addresses, as defined in IETF publication RFC 791, are 32-bit numbers that are split into four octets. Each octet is dot-separated and holds 8 bits of data. For convenience, the data in each octet is presented in decimal form. As such, every octet can hold a number between 0 and 255. An example of IPv4 would be 192.168.1.1.
Why Is IPv4 Being Replaced by IPv6?
Over the last couple of years, IPv4 is slowly being supplanted by its successor – IPv6. The transition is necessitated by the fact that all available IPv4 addresses have already been exhausted.
IPv6 addresses are four times longer than IPv4 addresses and hold 128 bits of data. While this might not sound like much, it amounts to a total of 340 undecillion unique addresses. An undecillion is one followed by 66 zeroes.
Are IPv4 and IPv6 Compatible?
Unfortunately, IPv4 and IPv6 addresses are not compatible with each other. As a result, we now have two separate Internet networks that are independent of one another. So, if you have a client that uses an IPv4 address and a server that only supports IPv6, then these two devices would not be able to communicate directly.
That said, the transition to IPv6 will take years to complete. As such, the incompatibility of the two networks poses a serious communication issue. To remedy that, special gateways have been developed that are able to translate IPv4 requests to IPv6 and vice versa.
What Are the Differences Between IPv4 and IPv6?
The major difference between the two Internet protocols is their length. IPv4 addresses are 32-bit long, while IPv6 addresses have a length of 128 bits. Due to this increased length, IPv6 addresses are represented by eight 16-bit numbers. Each 16-bit number is separated with a colon from its neighbors and is written in hexadecimal instead of decimal. An example IPv6 address is 2001:0db8:85a3:0000:0000:8a2e:0370:7334. Conversely, IPv4 addresses look like 192.168.1.1.
Conclusion
IPv4 addresses have been in existence for four decades already and have served us well. However, the number of devices that we connect to the Internet grows by the day and that number has already passed the total amount of available IPv4 addresses. As such, it is clear that the new IPv6 standard will carry the Internet forward for decades to come.
