How to view available network interfaces in Linux

Preface

The most common task after we install a Linux system is network configuration. Of course, you can configure the network interface when installing the system. However, for some people, they prefer to configure the network or change the existing settings after installing the system.

As we all know, in order to configure network settings in the command line, we must first know how many network interfaces are available in the system. This simple guide will list all possible ways to find available network interfaces in Linux and Unix operating systems.

Find available network interfaces in Linux

We can use the following methods to find the available network interfaces.

Method 1: Use ifconfig command

Using the ifconfig command to view network interfaces is still the most commonly used method. I believe there are still many Linux users who still use this method.

$ ifconfig -a

Sample output:

enp5s0: flags=4098<BROADCAST,MULTICAST> mtu 1500
ether 24:b6:fd:37:8b:29 txqueuelen 1000 (Ethernet)
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

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 Loopback)
RX packets 171420 bytes 303980988 (289.8 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 171420 bytes 303980988 (289.8 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

wlp9s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.225.37 netmask 255.255.255.0 broadcast 192.168.225.255
inet6 2409:4072:6183:c604:c218:85ff:fe50:474f prefixlen 64 scopeid 0x0<global>
inet6 fe80::c218:85ff:fe50:474f prefixlen 64 scopeid 0x20<link>
ether c0:18:85:50:47:4f txqueuelen 1000 (Ethernet)
RX packets 564574 bytes 628671925 (599.5 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 299706 bytes 60535732 (57.7 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

As shown in the above output, there are two network interfaces on my Linux machine, they are called enp5s0 (wired network card on the motherboard) and wlp9s0 (wireless network card). The lo is the loopback network card, which is used to access local network services. Usually its IP address is 127.0.0.1.

We can also use the same ifconfig in many UNIX variants such as FreeBSD to list the available network cards.

Method 2: Use the ip command

In the latest Linux versions, ifconfig command has been deprecated. You can use the ip command to list network interfaces, as follows:

$ ip link show

Sample output:

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
2: enp5s0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
link/ether 24:b6:fd:37:8b:29 brd ff:ff:ff:ff:ff:ff
3: wlp9s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DORMANT group default qlen 1000
link/ether c0:18:85:50:47:4f brd ff:ff:ff:ff:ff:ff

You can also use the following command to view it.

$ ip addr

$ ip -s link

Did you notice? These commands also display the status of connected network interfaces. If you look closely at the output above, you will notice that my wired NIC is not connected to the network cable (as indicated by the DOWN in the output above). Also, my wireless card is connected (as can be seen from the UP in the output above). For more details, you can check our previous guide to check the connected status of network interfaces in Linux.

These two commands (ifconfig and ip) are enough to view the available network cards in your Linux system.

However, there are other ways to list network interfaces in Linux, which we will see below.

Method 3: Use the /sys/class/net directory

The Linux kernel stores detailed information about network interfaces in the /sys/class/net directory. You can check the contents of this directory to see if the list of available interfaces matches the previous result.

$ ls /sys/class/net

Sample output:

enp5s0 lo wlp9s0

Method 4: Use the /proc/net/dev directory

In Linux operating systems, the file /proc/net/dev contains information about network interfaces.

To view the available network cards, just use the following command to view the contents of the above file:

$ cat /proc/net/dev

Sample output:

Inter-| Receive | Transmit
face |bytes packets errs drop fifo frame compressed multicast|bytes packets errs drop fifo colls carrier compressed
wlp9s0: 629189631 566078 0 0 0 0 0 0 60822472 300922 0 0 0 0 0 0
enp5s0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
lo: 303980988 171420 0 0 0 0 0 0 303980988 171420 0 0 0 0 0 0

Method 5: Use the netstat command

The netstat command can list a variety of different information, such as network connections, routing tables, interface statistics, masquerade connections, and multicast memberships.

$ netstat -i

Sample output:

Kernel Interface table
Iface MTU RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg
lo 65536 171420 0 0 0 171420 0 0 0 LRU
wlp9s0 1500 565625 0 0 0 300543 0 0 0 BMRU

Please note that netstat is deprecated, the replacement for netstat -i is ip -s link . Also note that this method will only list the activated interfaces, not all available interfaces.

Method 6: Use nmcli command

nmcli is a command-line tool used to control NetworkManager and report network status. It can be used to create, display, edit, delete, activate, deactivate network connections and display network status.

If you have NetworkManager installed on your Linux system, you can use the following command to list the available network interfaces using nmcli:

$ nmcli device status

or

$ nmcli connection show

Now you know how to find available network interfaces in Linux

If you know any other quick ways to find available network interfaces in Linux, please share them in the comment section below. I will check your comments and update this guide.

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