The ifconfig command is a powerful tool used to configure network interfaces on Unix-like operating systems, including macOS. It allows users to view and change the configuration of network interfaces, such as setting IP addresses, netmasks, and enabling or disabling interfaces. This command is essential for network troubleshooting and configuration tasks, making it a valuable skill for systems engineers and network administrators working in a macOS environment.

In macOS, ifconfig can be used directly from the Terminal application to manage network interfaces. This article will guide you through the basic usage of ifconfig on macOS, providing practical examples to help you understand how to use this command effectively.

Examples:

1. Viewing Network Interface Information:
To display information about all network interfaces on your macOS system, use the following command:

   ifconfig

This command will list all network interfaces along with their current configuration, including IP addresses, netmasks, and status.

2. Configuring an IP Address:
To assign a new IP address to a specific network interface (e.g., en0), use the following command:

   sudo ifconfig en0 inet 192.168.1.100 netmask 255.255.255.0

This command sets the IP address of en0 to 192.168.1.100 with a netmask of 255.255.255.0. Note that sudo is required to execute this command with administrative privileges.

3. Enabling or Disabling a Network Interface:
To disable a network interface (e.g., en0), use the following command:

   sudo ifconfig en0 down

To enable the network interface again, use:

   sudo ifconfig en0 up

4. Adding an Alias to a Network Interface:
You can add an alias (secondary IP address) to a network interface using the following command:

   sudo ifconfig en0 alias 192.168.1.101 netmask 255.255.255.0

To remove the alias, use:

   sudo ifconfig en0 -alias 192.168.1.101

5. Releasing and Renewing DHCP Lease:
To release the current DHCP lease on a network interface (e.g., en0), use:

   sudo ipconfig set en0 BOOTP

   sudo ipconfig set en0 DHCP

This sequence of commands forces the interface to release its current DHCP lease and request a new one.