Ifconfig

ifconfigis a command in Unix-like operating systems like Linux^[1], FreeBSD, OpenBSD, macOS for Ethernet network interface configuration.

In macOS, the ifconfig command functions as a wrapper to the IPConfiguration agent, and can control the BootP and DHCP clients from the command-line. Use of ifconfig to modify network settings in macOS is discouraged, because ifconfig operates below the level of the system frameworks which help manage network configuration. To change network settings in macOS from the command line, use /usr/sbin/ipconfig or /usr/sbin/networksetup.

ifconfig command is included in the net-tools package but not installed by default in RHEL since version 7^[2].

Configure 3 alias in en1 interface, https://ss64.com/osx/ifconfig.html:

sudo ifconfig en1 inet 192.168.10.2/24 add
sudo ifconfig en1 inet 192.168.20.2/24 add
sudo ifconfig en1 inet 192.168.30.2/24 add

or

sudo ifconfig en1 inet 192.168.10.2/24 alias
sudo ifconfig en1 inet 192.168.20.2/24 alias
sudo ifconfig en1 inet 192.168.30.2/24 alias

• Show interface configuration in Linux including ip addresses: ifconfig -a or ip a
• Show interface Ethernet network capabilities of your interface, such as speed, with: mii-tool -v YOUR_INTERFACE_NAME, mii-tool -v eth0
• Show all network inferfaces in Linux:^[3]

lspci | egrep -i --color 'network|ethernet'

lshw -class network

ifconfig -a

ip link show

ip a

cat /proc/net/dev

systemd/networkctl|networkctl list

nmcli|nmcli device show

• Learn about Linux Naming Schemes Hierarchy.

• netstat
• ipconfig Windows command
• networksetup (command) (macOS)

1. ↑ https://linux.die.net/man/8/ifconfig
2. ↑ https://lwn.net/Articles/710533
3. ↑ https://www.cyberciti.biz/faq/linux-list-network-cards-command/