The commands ifdown and ifup are used to configure network interfaces based on the system's existing distribution-specific configuration files. These files are typically located in /etc/network/interfaces or
/etc/sysconfig/network-scripts, depending on the Linux distribution. The ifdown command shuts down a network interface, while the ifup command brings up a network interface. These commands can be used to apply changes made to the configuration files without rebooting the system12.
The other commands are not related to network interface configuration. The ifconf command does not exist in Linux. The ifpause and ifstart commands are not standard Linux commands, but they may be aliases or scripts defined by some users or distributions. References: 1: NetworkConfigurationCommandLine - Community Help Wiki. 2: [How to Configure Network Static IP Address on RHEL/CentOS 8/7/6].