Operation Manual

You can check the current status of the network using the iwconfig command. Like ifconfig, the iwconfig command
allows you to check the status of a network interface and issue configuration commands. Unlike ifconfig, however, iwconfig
is specifically designed for wireless networks and includes specific features for this. Type the command name at the terminal as
follows:
iwconfig
The output of iwconfig, as shown in Figure 4-5, is split into the following sections:
• Interface Name—Each device has its own interface name, as with wired networks. If the interface is a wireless connection,
additional details will be shown. The default name for a Pi’s wireless connection is wlan0.
• Standard—The IEEE 802.11 wireless standards have a variety of different types, distinguished by a letter suffix. This
section lists the standards supported by the USB wireless adapter. For the example adapter, this reads IEEE 802.11bgn for
the network types it can address.
• ESSID—The SSID of the network to which the adapter is connected. If the adapter is not currently connected to a
network, this will read off/any.
• Mode—The mode that the adapter is currently operating in, which will be one of the following:
• Managed—A standard wireless network, with clients connecting to access points. This is the mode used for almost all
home and business networks.
• Ad-Hoc—A device-to-device wireless network, with no access points.
• Monitor—A special mode in which the card listens out for all traffic whether or not it is the addressee. This mode is
typically used in network troubleshooting for capturing wireless network traffic.
• Repeater—A special mode that forces a wireless card to forward traffic on to other network clients, to boost signal
strength.
• Secondary—A subset of the Repeater mode, which forces the wireless card to act as a backup repeater.
• Access Point—The address of the access point to which the wireless adapter is currently connected. If the adapter isn’t
connected to a wireless access point, this will read Not-Associated.
• Tx-Power—The transmission power of the wireless adapter. The number displayed here indicates the strength of the signal
that the adapter is sending: the higher the number, the stronger the signal.
• Retry—The current setting for the wireless adapter’s transmission retry, used on congested networks. This does not
normally need changing, and some cards won’t allow it to be changed.
• RTS—The adapter’s current setting for Ready To Send and Clear To Send (RTS/CTS) handshaking, used on busy
networks to prevent collisions. This is normally set by the access point on connection.
• Fragment—The maximum fragment size, used on busy networks to split packets up into multiple fragments. This is normally