What is IP block?

January 12, 2024

An IP block refers to a range or block of IP addresses that are consecutively allocated or associated with each other. These blocks of IP addresses are assigned for specific purposes, such as hosting multiple websites, managing a private network, or implementing security measures. Here are some features and aspects of IP blocks:

Table of Contents

  1. IP Address Range:
    • It consists of a range of IP addresses. The range is defined by the starting and ending IP addresses within the block. For example, an IP block might include addresses from 192.168.0.1 to 192.168.0.255.
  2. Subnetting:
    • It can be subdivided into smaller segments known as subnets. Subnetting allows network administrators to efficiently allocate IP addresses within an organization while maintaining hierarchical address structures.
  3. Classful and Classless Addressing:
    • Historically, IP addresses were divided into classes (Class A, B, C, etc.). Classless Inter-Domain Routing (CIDR) has become more prevalent, allowing for more flexible allocation of IP addresses. CIDR notation, such as 192.168.0.0/24, is commonly used to represent IP blocks.
  4. Public and Private IP Blocks:
    • It can be either public or private. Public IP blocks are routable on the public internet and are assigned by Internet Assigned Numbers Authority (IANA) or regional internet registries. Private IP blocks are reserved for use within private networks and are not routable on the internet.
  5. Network Address Translation (NAT):
    • IPV4 are often used in conjunction with Network Address Translation (NAT). NAT allows multiple devices on a private network to share a single public IP address. This is common in home and office networks.
  6. IP Block Ownership:
    • IP blocks are typically owned by organizations, internet service providers (ISPs), or hosting providers. These entities receive allocations of IP addresses from regional internet registries and may further allocate or subdivide them based on their needs.
  7. IP Address Leasing:
    • In some cases, IP addresses within a block can be dynamically assigned to devices using DHCP (Dynamic Host Configuration Protocol). This is common in environments where devices do not have static or permanent IP assignments.
  8. IP Geolocation:
    • It can be associated with specific geographic regions, and IP geolocation databases are used to map IP addresses to physical locations. This information is often used for various purposes, including targeted advertising and content delivery.
  9. Security Measures:
    • It play a role in network security. Firewalls and security devices may use IP blocking to restrict or allow access based on IP addresses. This is often employed to mitigate attacks or unauthorized access.
  10. Routing Protocols:
    • IP blocks are managed and routed using various routing protocols, such as Border Gateway Protocol (BGP), which is used for routing between different autonomous systems on the internet.
  11. IPv4 and IPv6 Blocks:
    • IP blocks can be associated with both IPv4 and IPv6 addresses. With the exhaustion of IPv4 addresses, the adoption of IPv6 has become more critical, and IP blocks for IPv6 are becoming increasingly important.

How IP Blocking Works:

A website host can track the IP address information of all the visitors to the website. Under normal circumstances, this can be used to see which users have visited which pages, verify geolocation data against the IP address, or track other activity (especially when supplemented with cookies on the user’s web browser).

However, a web host can also add IP addresses to a ban list (i.e. a blacklist). Any connection coming from an IP address on the blacklist is automatically rejected. This usually results in a “connection denied” or similar error message for the blocked device’s user.

Whitelisting, or the practice of only allowing pre-approved IP addresses to connect to your website, is a wholly unrealistic option for any company that wants to bring in new customers via online campaigns. This is because you’d have to add each new contact to the whitelist before you could have them fill out forms on your website.

Understanding IP blocks and their management is essential for network administrators, IT professionals, and organizations to effectively allocate and manage IP addresses within their networks. It also plays a crucial role in internet routing and the overall functioning of the global internet infrastructure.