theshell.ch/site/pages/cmd/interm/ifconfig.html

---
layout: page
category-page: intermediate
category-title: Intermediate commands
tags: command ifconfig
author: Matteo Omenetti
title: ifconfig
---

The command <code>ifconfig</code> stands for <i>Interface CONFIGuration</i>. It is used
to configure, control, and query network interface parameters of your system.<br>
If you try running this command with no arguments, it will simply display information
about all network interfaces currently active.<br>

{% highlight bash %}
    ifconfig
{% endhighlight %}

The output sill resembles something like this, of course it changes from machine
to machine:

<pre>
en5: flags=8863 UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST mtu 1500
    ether ac:de:48:00:11:22
    inet6 fe80::aede:48ff:fe00:1122%en5 prefixlen 64 scopeid 0x8
    nd6 options=201 PERFORMNUD,DAD
    media: autoselect (100baseTX full-duplex)
    status: active

ap1: flags=8802 BROADCAST,SIMPLEX,MULTICAST mtu 1500
    ether f2:18:98:41:74:42
    media: autoselect
    status: inactive
    ...
</pre>

If you want to view the configuration of all network interfaces, not just the ones
currently active, you can use flag <code>a</code>.

{% highlight bash %}
ifconfig -a
{% endhighlight %}

If you want to view the configuration of a specific interface, you can specify
the name of the interface you want to view after the command <i>ifconfig</i>:

{% highlight bash %}
ifconfig ap1
{% endhighlight %}

This command will show only the configuration of ap1.<br>

To enable an interface, you can use the command ifconfig with the name of the interface
you want to enable, followed by the key word <code>up</code>.<br>

However, enabling or disabling a device, is a privilege reserved for the super user,
therefore you also have to use the command <code>sudo</code>.

{% highlight bash %}
   sudo ifconfig ap1 up
{% endhighlight %}

To disable an interface, you can follow the same procedure, this time using
the key word <code>down</code>.

{% highlight bash %}
   sudo ifconfig ap1 down
{% endhighlight %}