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What is IPv4?

What does IPv4 stand for?

IPv4 is the fourth version of the internet protocol that routes most internet traffic and other packet-switched networks. It stands for the Internet Protocol version 4 and is a widely used protocol in data communication over various kinds of networks despite its limited 32-bit address space. The IPv4 is also the underlying technology that makes it possible for computer users to connect to their gadgets and devices to the internet. The Internet Engineering Task Force (IETF) introduced this in 1982.  However, with a cap short of only about 4.3 billion available unique addresses, the people behind the IPv4 saw the fast decline of available unique addresses. But with witty initiative and resourcefulness, its life was further extended and did not fully dry up until 2011.

Definition of IP Address

The Internet Protocol Address or IP address, for short, is a unique identifier for computers, devices and gadgets that are connected to a network. This identifier makes it possible for the gadgets or devices to locate and communicate with each other. Initially, the main types of devices that need such address are network devices like your computers, servers, routers and even your printers. But as more things are embedded with sensors, software and are designed to connect and exchange data with other devices, or the Internet of Things, the list for devices that requires an IP address also grew. This includes cellphones, TV, refrigerators, vehicles, or anything that can receive and exchange information over a network.

Understanding What IPv4 Addressing is

This is a series of four 8-bit binary digits which is divided by a decimal point. Although any numbering system can be used to stand for a unique 32-bit number, but most often, an IP address is expressed in a dot-decimal format.

Some of the most common Sites and its IP Address includes:

  • with a dot-decimal notation of and has a Binary format of 10101100.11011001.10101000.11101110.
  • has the following corresponding details and 00011111.00001101.01010100.00100100.
  • has a dot-decimal notation of and a binary format of 10010111.01100101.00000000.01010100.

Early IPv4 Routing

Early on, the first octet was defined as a network identifier. But with only about 256 unique values, the number of available networks almost immediately ran out. Over the years, numerous changes have been made, and these changes extended the life of IPv4. Initially, the division of the available addresses were sorted into different classes: A,B,C,D and E.

This system classifies which class a network should be in basing on its first octet.

  • Class A Network’s first octet starts with a zero. The first octet recognizes the network. Class A supports 127 networks each having 16 million hosts.
  • The network of Class B starts with 10. The first and second octets recognize and classify the network. This class supports 16,000 networks with each network having 65,000 hosts.
  • Class C starts with 110 as its first octet. The first three identify the network. It then supports 2 million networks, with 254 hosts each.
  • Class D on the other hand starts with 1110. It is reserved for multicast groups.
  • Class E is also reserved but for future usage, and its first octet begins with 1111.

These classes use different number of bits. This is to find out the network affecting how many networks and hosts each of these classes can accommodate.   Example: The first three octets of Class C defined the network, then, the fourth octet described the hosts on the network.

The IETF changed the class system or the “classful system” with a subnet mask. The replacement, the subnet mask, allowed for the distribution of addresses on any address-bit boundary.

IPv4 Today

The Classless Inter-Domain Routing or CIDR was first introduced in 1993. It gave a greater flexibility when it comes to allocating blocks of addresses. It also adds a suffix to the IP address in order to determine the number of leading bits represent the network address. For IPv4, it is the number from 0 to 32. The higher the suffix, the lesser available host addresses available on the network.

Not only did the CIDR extend the life of IPv4, it also slowed the growth of routing tables. This is possible by reducing the number of wasted addresses, addresses which crowds the class system. CIDR is still being widely used as a network routing method until now both for the IPv4 and IPv6.

IPv4 Address Exhaustion

In 2011, the IPv4 distributed its last address blocks to the five regional internet registries. One of these registries completely ran out of addresses within the next few months. Individual internet service providers (ISP) were able to keep IPv4 alive. They have done this by sheer ingenuity and by recycling addresses whenever it becomes available.

As mentioned earlier, the IPv4 has only about 4.3 billion available addresses. And with the rapid internet growth and the so called Internet of Things, the number of available addresses is immediately threatened, and quickly diminished. To resolve the situation, the IETF released IPv6 with its 128-bit address space for nearly infinite 340 undecillions, which is 340 with 37 zeroes, available addresses.


IPv4 and IPv6 utilize CIDR in order to handle both their network and host addressing. However, the two versions are not totally interchangeable. The latter fixes many other networking problems that are inherent in the former, like smaller routing tables, simplified packet headers, and IPv4 uses multicast instead of broadcast.

A single device or gadget can support the two IPs (IPv4 and IPv6) with the dual-stack IP. This allows a single router, switch or server to process either address space. You cannot however connect to a device or gadget that is solely dedicated to IPv6 using the IPv4 connection, likewise you cannot connect to an IPv4 only gadget using the IPv6 connection.

A dual-stack IP means that the device or gadget can run IPv4 and IPv6 in parallel. It permits the hosts to reach IPv4 and IPv6 contents simultaneously, offering a flexible co-existence approach.

IPv4 Speed

The load that the IPv4 carries in order to extend the number of addresses does have an effect on the network speed. In the IPv6 environment, it can outperform its predecessor. But the IPv6 still need some work, and depending on local architecture, thus, the older version can still outrun and outperform the IPv6. The Happy Eyeballs, an algorithm that is being used by some browsers, can test the speed of these protocols and will use the faster network protocol.

Domain Name System for IPv4 and IPv6

The DNS supports these two network protocols. It stores the IP addresses for either or both and reacts to each request for domain name resolution with the two IP addresses. It also puts the IPv4 addresses into the A record and stores the newer version’s addresses in the AAAA record. At this point, the client can already decide which IP to use.

Monitoring your IPv4 Addresses

The IP address is susceptible to hacking. It is vulnerable to attacks. If a hacker gains access to the DNS settings, they can alter, modify and change the IP addresses. They can then direct users to malicious sites or prevent them from gaining access to a destination. To protect the most vulnerable part of the networking protocol, a DNS monitor can verify the IP address. It can do so once per minute. It can also check and verify other records that are found in your DNS like the MX and NS records.

Monitor the Two Internet Protocols

Although the two protocol courses through the same server, it does not automatically mean that they work. Monitoring the two protocols is possible with the use of uptime monitoring. This is ideal for websites and web services. To monitor IPv4 and IPv6 openly, choose either protocol in the monitor settings and select the monitoring checkpoints. For the IPv6, choose checkpoints that natively support IPv6 or pick them all with the IPv6 simulation over the older IP version.

Which Protocol Does my site support?

Using the DNS Tool, enter a domain name example: then click start test.

The free DNS Lookup Tool sorts out the address. That is, the tool asks the DNS system and retrieves your DNS records. Run through the results and search for the A and AAAA records. You can have several of either or none of the other.

  • If the results that came out have included an A record, the site supports IPV4 as most sites usually do.
  • If it includes an AAAA record, then it supports the newer version which is less common.
  • If the site has results for both IPs, then the site supports both IPv4 and IPv6.

To make it easier for you, here are several key points about IPv4 and IPv6

  • The most widely used protocol is IPv4. It is used more than its newer version, IPv6.
  • The latter version resolved the address exhaustion issue of IPv4.
  • The older version uses a 32-bit addressing system.
  • Both protocols can exist on the same gadget using the dual-stack IP.
  • The algorithm that enables the device or browser to select the faster protocol from a destination is Happy Eyeballs.
  • IPv6 will ultimately replace the older IPv4. IPv6 acceptance grows by as much as 5% every year.
  • A website or service while available on a protocol may not be on another. Monitor both IP addresses for availability.