index.docbook

Linux/Unix下无限网卡配置和管理程序

There are some minor additional things to be said.</para><para>
First, there is a feature
named "Acoustic Scanning". If this option is enabled, the connection quality
is converted into an acoustic signal. A higher signal quality leads to a
higher frequency of the "beep" output and to a more rapid beeping. If you've
ever seen the Star Trek(tm) series you will see some parallels to their
"tricorders". :-)
</para><para>
A second feature is "silent logging". It just means that KWiFiManager will log
the name of the network you are connecting to every time your network changes.
This option is most useful when searching for the special network name "ANY".
In this mode, the card will log into any network it finds. The logfile's
position is $HOME/.wireless-log
</para><para>
The third thing is just a note: In the file menu, there is an entry "Disable
radio". This option is NOT IMPLEMENTED YET. But please don't blame me, the
problem is in the kernel drivers for Wi-Fi cards. The driver simply doesn't
support it.
</para>
</sect2>
</sect1>
<sect1 id="panelapplet">
<title>The panel applet</title>
<para>
The panel applet is the second part of the KWiFiManager suite. It is a shared
library tat can "dock" into KDE's panel ("Kicker"). It only displays the
signal quality as icon and as text (see 3.1.1.1 for details).</para><para>
With it's light-weight size it is best suitable for
continuous use. If you don't want the "huge" KWiFiManager main app on your
screen all the time, just use the applet.</para>
<sect2 id="applet-launch">
<title>Launching the applet</title>
<para>
The panel applet can be added to your panel by right-clicking on the panel
and selecting "Add, applet, KWiFiManager applet". Another way to start the
applet is to click on its desktop file, which can be found on your disk
in the directory: $KDEDIR/share/apps/kicker/applets. That way it will not
dock into the panel but free-float on your desktop.
However, the first method is easier and should be preferred.</para>
<para>The panel applet can be minimally configured: it can optionally flash in yellow,
orange and red colors when the signal quality level is very low. To enable or
disable this feature, right-click on the applet's "handle" left of the icon and select
<guimenuitem>personal settings</guimenuitem>.</para>
</sect2>
<sect2 id="applet-tooltip">
<title>Tooltip information</title>
<para>
If you hover above the applet for a few seconds, you will be shown a tooltip with a few
additional information, namely:
<itemizedlist>
<listitem><para>your local IP address</para></listitem>
<listitem><para>the network name, if one is set</para></listitem>
</itemizedlist>
</para>
</sect2>
<sect2 id="main-from-applet">
<title>Starting KWiFiManager main application from the panel applet</title>
<para>
A single click on the applet launches (either with left-click or right-click, as you prefer) the KWiFiManager main application.
</para>
</sect2>
</sect1>
<sect1 id="cc-module">
<title>The Control Center module</title>
<para>
The configuration module in the KDE Control Center is perhaps the most useful part
of the KWiFiManager suite. Here you can actually change
the basic settings of your wireless LAN card. The module
can manage up to four independent configurations for the
card, and it can even automatically set your card up whenever
you log into KDE.
Since establishing a network connection is a possible security hazard, any changes
to the configuration can only be done by root.
</para>
<sect2 id="conf-tab">
<title>The Configuration Tabs</title>
<para>
The upper part of the control center module consists of four tabs labelled
<guilabel>Config 1</guilabel> thru <guilabel>Config 4</guilabel>. Each of
these tabs can hold a configuration for your WLAN card.</para>
<para>
The most important settings are always visible, the cryptography and power
management options are only shown when activated.
The perhaps most important element in each configuration tab is the field
<guilabel>Network name</guilabel>. Here you can specify which network you
would like to log into. You can either specify the name of your network
directly, or you can try a scan on all available networks by setting the network
name to <userinput>ANY</userinput>.
</para><para>
In addition to the network name, you have to specify the type of network to log
into. That's the purpose of the button group <guilabel>Operation mode</guilabel>.
The option <guilabel>infrastructure</guilabel> means that the network consists
of designated base station, so-called "access points" or "residential gateways". This is the
most common operation mode for company networks. The second option,
<guilabel>peer-to-peer</guilabel> means that your network is just a direct connection
between computers, without access points.
</para>
<para>
On the right-hand side of the configuration tab, you can optionally set the connection
speed for your connection. The setting <guilabel>auto</guilabel> should do for
most uses, since the card will determine the appropriate speed itself. However, if
you find that the speed changes every few seconds, for example when you have a weak
connection, you can set the speed manually.
</para>
<para>
Below these configuration items you will find a field named <guilabel>Execute script on
connect:</guilabel>. Here you can enter the name of a script to execute. It will be
executed whenever you hit the <guilabel>Activate configuration</guilabel> button and, optionally,
automatically when you start the Control Center module. The script will have root rights.
This may lead to problems if you want to start an X application in the script and the X server
belongs to someone else than root. You can make such scripts work correctly if you execute the
X application via <userinput>kdesu -u USERNAME -c COMMAND"</userinput>.
</para>
<para>
The lower-left part of each configuration tab holds the cryptograhy settings. These
settings are only shown if you check the box <guilabel>Use cryptography?</guilabel>.
If shown, you are presented with numerous options:
<itemizedlist>
<listitem><para><guilabel>Key to use</guilabel>: you can define up to four secret keys for
each configuration, in this field you can set which one you actually want to use to
encrypt network traffic</para></listitem>
<listitem><para><guilabel>Crypto mode</guilabel>: When encryption is activated, there are
two ways to deal with incoming non-encrypted packets: discard or allow. When you set
your card for <guilabel>Open mode</guilabel>, the card will also listen to non-encrypted
packets. <guilabel>Restricted mode</guilabel> will only allow encrypted network packets,
any other packets are discarded.</para></listitem>
<listitem><para><guilabel>Crypto keys</guilabel>: This box lets you specify the secret keys
to use for cryptography. The small box <guilabel>String?</guilabel> sets whether the key
you enter to right is either a string like <userinput>MY_CRYPTO</userinput>, or, if
not checked, a hex value like <userinput>0A2FEE91</userinput>. To protect your passwords,
only asterisks will be shown when you enter a password.</para></listitem>
</itemizedlist>
Be aware that the built-in cryptography support (named WEP for Wireless Equivalent Privacy) is
not very safe at all. See appendix for details.
</para>
<para>
The last configuration element that remains to be described is the power management.
When checking the box <guilabel>Enable Power Management</guilabel> you will be presented
some options that can help you save energy.
The first two input fields named <guilabel>Sleep duration (ms)</guilabel> and
<guilabel>Awaken time (ms)</guilabel> describe the periodicity of network scans
for your wireless LAN card. The card will turn the radio antenna off for the time
period in milliseconds specified in <guilabel>Sleep duration</guilabel>. Afterwards
it will be active for <guilabel>Awaken time</guilabel> and will in that time scan
for a network connection. If no network connection is found, it will go to sleep again
and the cycle begins again.
The box named <guilabel>Receive packets</guilabel> below lets you specify which packets
the card should listen to when awaken. You can either select <guilabel>Unicast only</guilabel>
(which will only let your card listen to packets sent specifically to your card),
<guilabel>Multi/Broadcast only</guilabel> (will only listen to packets sent to multiple machines
and discard packets directed to your card) or <guilabel>Both</guilabel>. Most people
should select the default value <guilabel>Both</guilabel>.
</para>
</sect2>
<sect2 id="auto-configuration">
<title>Auto-configuration on Control Center Module startup</title>
<para>
If you wish, you can make KWiFiManager initialize your wireless LAN card whenever you start the Control
Center Module. To do so, check the box <guilabel>Load preset configuration on Control Center Module startup</guilabel>
and select the number of the configuration you want to use in the listbox below. If you
want to set the card to these settings at once, push the button <guilabel>Activate configuration</guilabel>.
</para>
</sect2>
<sect2 id="autodetect">
<title>Autodetecting your device</title>
<para>
KWiFiManager needs to know the interface name of your wireless LAN card to change
any settings. You can either enter the information (e.g. <userinput>eth1</userinput> or <userinput>wlan0</userinput>)
manually in the input field right of <guilabel>Settings apply to interface:</guilabel>, or let KWiFiManager auto-detect the interface. To do so, push the button
<guilabel>Autodetect interface</guilabel>. This will perform a scan on all interfaces
listed in <filename>/proc/net/dev</filename> to find your card. The result of the scan
will show up in the input field left of the button. If the field remains empty, no card
was found.
Please note that KWiFiManager uses the wireless extensions to detect cards. If you
use a card controlled by the wlan-ng package, KWiFiManager only shows correct results
if your driver has a compatibility layer for the wireless extensions built-in.
</para>
</sect2>
</sect1>
</chapter>
<chapter id="append">
<title>Appendix</title>
<para>This chapter contains some extra information of items concerning wireless LAN that are not directly related
to KWiFiManager.</para>
<sect1 id="macaddress">
<title>Notes on the MAC address display in Ad-hoc mode</title>
<para>
At first glance, the MAC address in the field <guilabel>Access Point</guilabel> seems to be wrong in Ad-hoc mode
because it changes the first two bytes of the MAC address to "02". But actually, this is a hardcoded feature
in wireless LAN cards.
</para>
<para>
Usually a card is connected to a "real" access point. Then the correct MAC address is shown. If you change to
Ad-hoc (or "Peer-to-peer") mode, one of the computers must act as a server for the other computers. The first
computer that enters a network, will set itself as server. So, all other computers connecting to the same Ad-hoc
network will see that first computer as network server. But since this computer is not a "real" server (that is,
it is not a permanently available access point), clients should be aware that the network they are connecting
to is not a permanent one. IEEE standards for MAC addresses have a place reserved for such occasions: MAC addresses
that are not globally valid have "02" as the first two bytes (these addresses are called "locally administered" addresses).
You can compare this to the non-global IP addresses like 192.168.*.*.
So, the implementors of wireless networking agreed to give these "virtual" network servers a MAC address that is
within the "locally administered" scope. To keep this virtual MAC address unique, they used a little trick: they
only changed the first two bytes of the MAC address of the wireless LAN card, and since the remaining ten bytes are still unique in the world,
they have a unique address to use as network server.
</para>
</sect1>
<sect1 id="wep">
<title>Security considerations on WEP cryptography</title>
<para>
WEP cryptography is not very secure at all. A recent paper from cryptography analysts called the encryption
algorithm "kindergarten cryptography". Actually, software exists that exploits a huge security hole in the
encryption standard. This software listens to the encrypted network traffic, analyses it, and after only
a few hours it reveals the password to enter the network in clear text. The more traffic on the network, the
easier it is to find out the password.
</para>
<para>
If you are truly concerned about your security, do NOT use WEP. If you are just setting up a two-computer
home network, well, then I guess WEP should do.
</para>
<para>
There are many alternatives to WEP encryption. You could only use SSH to communicate over the network. SSH is
a program suite that encrypts data with its own algorithm, which is very secure.
Another option is to use PPTP, the Point-to-Point-Tunneling protocol. However, even PPTP seems to be a bit leaky
concerning encryption security.
And finally, you could set up an IPSec tunnel for your encrypted connections. As of yet, this encryption seems
to be very safe and flexible.
</para>
</sect1>
</chapter>
<chapter id="credits">
<title>License and contributors</title>
<para></para>
&underFDL;
&underGPL;
<para>The program is written by Stefan Winter <email>[e-mail]</email>.</para>
</chapter>
&documentation.index;
</book>