ipset is a utility in Linux used for managing sets of IP addresses, ports, or other IP-related objects. It is a powerful tool that can be used to create and manage lists of IP addresses and related data efficiently. ipset is particularly useful for implementing firewall rules, managing access control lists, and other network-related tasks.

Here are some common use cases for ipset:

  1. Firewall Rules: You can use ipset in combination with a firewall tool like iptables to create efficient and flexible rules for filtering network traffic. This can help in blocking or allowing specific IP addresses or address ranges.
  2. Intrusion Detection/Prevention Systems (IDS/IPS): Some network security tools and scripts use ipset to maintain lists of known malicious IP addresses for blocking or alerting purposes.
  3. Rate Limiting: ipset can be used to maintain a list of IP addresses for rate limiting incoming connections. For example, you can limit the number of incoming requests from specific IP addresses to prevent abuse.
  4. Access Control: It’s commonly used for controlling access to services, such as allowing only certain IP addresses to access a service.

ipset provides different types of sets, including:

  • hash:ip for sets of IPv4 addresses.
  • hash:ip,port for sets of IPv4 addresses and ports.
  • hash:mac for sets of MAC addresses.
  • And more.

To use ipset, you’ll need to install the ipset package if it’s not already installed on your Linux system. The specific commands for creating, modifying, and managing IP sets can vary depending on your use case and the type of set you are creating.

Here are some common commands:

  • To create a new IP set: ipset create myset hash:ip.
  • To add an IP address to a set: ipset add myset
  • To list the members of a set: ipset list myset.
  • To delete a set: ipset destroy myset.

Keep in mind that proper configuration and usage of ipset may require root (administrative) access to your Linux system. Additionally, the specific commands and options may vary depending on your Linux distribution and the version of ipset installed. Be sure to consult the documentation and man pages for ipset on your specific system for detailed information.