If you enter the command ifconfig in the shell for modern Linux operating systems, you will see command not found.

-bash: ifconfig: command not found

ifconfig is the utility for viewing and setting the network configuration on Red Hat, Fedora, CentOS, Debian, and Ubuntu Linux systems. The command includes the net-tools package, which has been replaced by the iproute2 package.

net-tools – ifconfig installation

The ifconfig binary is supplied with the Debian net-tools package. Install the package with the following command, which is available under the default repositories.

$ sudo apt install net-tools -y

Then ifconfig can be run to check the network configuration. The following command displays details for all interfaces configured on a Debian system.

$ ifconfig

For RHEL 8 and CentOS 8, the net-tools package is provided with the Manager YUM package.

$ sudo yum -y install net-tools

NOTE: The ifconfig program is deprecated! Replacement is given by the commands ip addr and ip link.

ifconfig shows the output of the network interfaces and their configuration.

$ ifconfig
ens192: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
        inet 10.127.0.123 netmask 255.255.255.0 broadcast 10.127.0.255
        inet6 fe80::20b:25ff:fefb:28db prefixlen 64 scopeid 0x20 <link>
        ether 00:0b:25:fb:28:db txqueuelen 1000 (Ethernet)
        RX packets 103153 bytes 86175369 (82.1 MiB)
        RX errors 0 dropped 519 overruns 0 frame 0
        TX packets 47536 bytes 42444582 (40.4 MiB)
        TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
        inet 127.0.0.1 netmask 255.0.0.0
        inet6 ::1 prefixlen 128 scopeid 0x10<host>
        loop txqueuelen 1000 (Local Loop)
        RX packets 0 bytes 0 (0.0 B)
        RX errors 0 dropped 0 overruns 0 frame 0
        TX packets 0 bytes 0 (0.0 B)
        TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0</host> </UP,LOOPBACK,RUNNING> </UP,BROADCAST,RUNNING,MULTICAST>

Run the new utility as follows.

$ ip addr
1: lo: <LOOPBACK,UP,LOWER_UP>mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: ens192: <BROADCAST,MULTICAST,UP,LOWER_UP>mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 00:0b:25:fb:28:db brd ff:ff:ff:ff:ff:ff:ff
    inet 10.127.0.123/24 brd 10.127.0.255 scope global noprefixroute ens192
       valid_lft forever preferred_lft forever
    inet6 fe80::20b:25ff:fefb:28db/64 scope link
       valid_lft forever preferred_lft forever</BROADCAST,MULTICAST,UP,LOWER_UP> </LOOPBACK,UP,LOWER_UP>

The ifconfig eth0 command is replaced by ip link.

$ ip link
1: lo: <LOOPBACK,UP,LOWER_UP>mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00:00
2: ens192: <BROADCAST,MULTICAST,UP,LOWER_UP>mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000
    link/ether 00:0b:25:fb:28:db brd ff:ff:ff:ff:ff:ff:ff</BROADCAST,MULTICAST,UP,LOWER_UP> </LOOPBACK,UP,LOWER_UP>

To output the routing table, the ip route command is executed instead of route.

$ ip route
default via 10.127.0.1 dev ens192 proto static metric 100
10.127.0.0/24 dev ens192 proto kernel scope link src 10.127.0.123 metric 100