user_guide.html

TTYLINUX迷你代码 TTYLINUX迷你代码

</ul>

<p>
The above is for dialup using a modem. If you want to use ISDN dialup,
you need to know the following:

<p>

<ul>
<li>the phone number of your ISP, i.e. <tt>1-800-12345678</tt>
</li>
<li>your user name at the ISP, i.e. <tt>joeuser</tt>
</li>
<li>your password at the ISP, i.e. <tt>joepass</tt>
</li>
<li>the phone number you want to use for dialing out
</li>
<li>whether you want to use automatic or manual dialing
</li>
</ul>

<p>
Edit the file <tt>mnt/etc/isp.conf</tt> and change the settings there to
your liking. Note that ttylinux only knows about providers that
launch a PPP session immediately after dialup (which should be true
for almost all providers these days), so if some special
procedure is needed to log you in, your Internet connection will not
work with ttylinux. The ttylinux approach will work with almost all
providers in Germany, but I don't know about other countries.

<p>
For ttylinux to use ISDN, you need to have <tt>USE_ISDN=yes</tt>
in <tt>/etc/isp.conf</tt>, the default is not to use ISDN. Obviously, you
also need a kernel with ISDN support and hardware support for your ISDN
hardware. If you need kernel modules to run your ISDN hardware, you
will also need to add those and a suitable <tt>/etc/modules.conf</tt> to 
the ttylinux filesystem.

<p>
Once you are finished making changes, unmount the filesystem and  run
<tt>gzip</tt> to compress it again:

<p>
<pre>
  umount mnt
  gzip -9 rootfs
</pre>

<p>
You are now ready for the real installation.

<p>
Note that this section has only covered the minimum customization
needed to run ttylinux. There is more to tune, have a look at the
system guide (section <a href="#sysguide">3</a>) below for information. If you aim
at the approach of running ttylinux from ramdisk, you must
configure everything for your needs before you continue the installation,
so it may be a wise idea to read the system guide section before you
countinue. If you install to a hard disk, you can always configure
things later.

<p>

<h2><a name="SECTION00036000000000000000">
<span class="arabic">2</span>.<span class="arabic">6</span> Installation by hand</a>
</h2>

<p>
I am assuming that you use <tt>LILO</tt> (short for Linux Loader) as your
boot loader. You can also use others like <tt>loadlin</tt>, but you will
obviously need some <tt>LILO</tt> experience to convert the <tt>LILO</tt>
example given here to some other boot manager. I am also assuming
that you want to add ttylinux to an existing LILO setup that is
already used to boot other (Linux) systems on your machine.

<p>
If you want to use the <tt>syslinux</tt> boot loader to load ttylinux
from a <tt>FAT</tt> filesystem, please see the appendix on creating a
bootable CD-ROM (appendix <a href="#makecdrom">A</a>) for an example.

<p>
Put the <tt>rootfs.gz</tt> image and the Linux kernel you want to use to run
ttylinux into the directory that holds your other boot files, most
likely this will be <tt>/boot</tt>. Let us assume your kernel image file is
called <tt>bzImage-ttylinux</tt>. You now need to add the following section
to <tt>/etc/lilo.conf</tt>:

<p>
<pre>
  image=/boot/bzImage-ttylinux
      label=ttylinux
      initrd=/boot/rootfs.gz
      root=/dev/ram0
      read-only
</pre>

<p>
Now rerun the <tt>LILO</tt> installer by typing <tt>/sbin/lilo</tt>.
On your next boot, you can enter <tt>ttylinux</tt> on the <tt>LILO</tt> boot
prompt to boot ttylinux. That is all, you are now ready to try ttylinux.

<p>
If you want to install onto hard disk, you need to have a partition
of at least 4 megabytes size available. Assuming this partition is
<tt>/dev/hda8</tt>, do the following, using the file <tt>ttylinux-hd.tar.gz</tt>
obtained above (in section <a href="#customize">2.5</a>):

<p>
<pre>  
  mke2fs /dev/hda8
  mount -t ext2 /dev/hda8 mnt
  cd mnt
  tar xvzf ../ttylinux-hd.tar.gz
  cd ..
</pre>

<p>
Now do the customization as outlined above. You will also need to
change the root device configured in <tt>mnt/etc/fstab</tt>. Once you are
done, you just need to unmount the partition:

<p>
<pre>     
  umount mnt
</pre>

<p>
Now you can setup <tt>LILO</tt> as explained above, only change the line for
the root filesystem to <tt>root=/dev/hda8</tt> and remove the <tt>initrd</tt>
line. Ready to go.

<p>

<h1><a name="SECTION00040000000000000000"></a>
<a name="sysguide"></a>
<br>
<span class="arabic">3</span> System guide
</h1>

<p>
This section gives a short overview over the system, its configuration,
and some of the installed programs.

<p>

<h2><a name="SECTION00041000000000000000">
<span class="arabic">3</span>.<span class="arabic">1</span> Basic Features</a>
</h2>

<p>
On bootup, ttylinux provides 6 text consoles for login. The default
setup has two user accounts: <tt>root</tt> (the administrator account)
with password <tt>root</tt> and <tt>guest</tt> with password <tt>guest</tt>.

<p>
The <tt>syslogd</tt> and <tt>klog</tt> daemons are running and log kernel
and system messages to the file <tt>/var/log/messages</tt>.

<p>
If you need a text editor, <tt>e3</tt> is installed. Simply invoke it by
typing <tt>e3</tt> <tt>/path/to/filename</tt>. A help screen is available by
pressing <tt>Alt-H</tt>. <tt>e3</tt> understands a lot of the old WordStar
commands, so it feels a bit like WordStar, an old Borland IDE, or the
common Linux editor <tt>joe</tt>. For those accustomed to different
editors, <tt>e3vi</tt> will startup <tt>e3</tt> in <tt>vi</tt> emulation
mode (<tt>e3em</tt> for <tt>emacs</tt> emulation mode, <tt>e3pi</tt> for
<tt>pico</tt> emulation mode).

<p>
For manipulation of users, groups and passwords, the tools <tt>passwd</tt>,
<tt>adduser</tt>, <tt>addgroup</tt>, <tt>deluser</tt>, and <tt>delgroup</tt> are
present.

<p>
If you have not changed the timezone and keyboard settings as outlined
in the customization section (<a href="#customize">2.5</a>, above), ttylinux will use
its default settings. The default timezone is UTC, the default keyboard
mapping is for a US keyboard.

<p>
The <tt>inetd</tt> super-server and the <tt>dropbear</tt> SSH server are
running by default. A telnet server will be forked by <tt>inetd</tt> when
a telnet connection comes in.

<p>
ttylinux includes a basic packet filtering firewall which is
enabled by default on the dialup interface. Note that the telnet
server is not visible from the external side of the dialup
interface in the default firewall configuration.

<p>

<h2><a name="SECTION00042000000000000000">
<span class="arabic">3</span>.<span class="arabic">2</span> Bootup and Shutdown</a>
</h2>

<p>
On system bootup, the init process runs the script
<tt>/etc/rc.d/rc.sysinit</tt> to get the system up. The script will do the
usual business of checking  and remounting the root filesystem and will
start up basic networking.

<p>
After that is done, <tt>rc.sysinit</tt> will run all executables from the
directory <tt>/etc/rc.d/rc.start</tt>. It does not matter whether these are
scripts or compiled programs. All executables will be passed the
parameter <tt>start</tt>. For example, if there is a script called
<tt></tt>runme, <tt>rc.sysinit</tt> will execute <tt>runme</tt> <tt>start</tt>.

<p>
The default initscripts that come with ttylinux are stored in the
directory <tt>/etc/rc.d/init.d</tt>. Those that need to be run at bootup are
symlinked into the <tt>rc.start</tt> directory. If you want to write your own
initscripts, place them in the <tt>init.d</tt> directory and place a symlink
in the <tt>rc.start</tt> and perhaps also in the <tt>rc.stop</tt> directory.

<p>
If you don't want to write your own script, you can also add commands
to the file <tt>/etc/rc.d/rc.local</tt> - this script will be run at the very
end of the boot process, after all others scripts have run.

<p>
On shutdown, the script <tt>/etc/rc.d/rc.reboot</tt> gets run. This will run
all the programs from the <tt>/etc/rc.d/rc.stop</tt> directory, and each program
will be passed a <tt>stop</tt> parameter. Our example script called <tt>runme</tt>
would be executed as <tt>runme</tt> <tt>stop</tt>.

<p>
Both scripts from <tt>rc.start</tt> and <tt>rc.stop</tt> will be run in ASCII
order. If you need them to run in a specific order, you could for
example use names like <tt>01.first</tt> and <tt>02.second</tt>. This is how 
the scripts  that come with ttylinux are named. Everything in <tt>rc.start</tt>
and <tt>rc.stop</tt>  should be a symlink, so you can simply remove that
link if you want to disable a specific script.

<p>
Initscripts can also be called manually in case you want to start  or
stop something while the system is running. To make this  easier, a
helper script called <tt>service</tt> is provided. For example:

<p>
<pre>     
  service inetd stop
</pre>

<p>
will stop the <tt>inetd</tt> server daemon. All scripts (except <tt>pppconf</tt>,
which understands few options) know about the options <tt>start</tt>,
<tt>stop</tt>, and <tt>restart</tt> that do the obvious things. Some scripts also
know about <tt>status</tt> and <tt>reload</tt> for displaying status information
and for reloading service configuration files.

<p>
All scripts will print a list of supported options if they are called
with no option present.

<p>

<h2><a name="SECTION00043000000000000000">
<span class="arabic">3</span>.<span class="arabic">3</span> Using PPP dialup</a>
</h2>

<p>
What to put into <tt>/etc/isp.conf</tt> to configure the dailup information
is outlined above in the customization section (<a href="#customize">2.5</a>, above).
What you will find here is an overview of how to actually use the PPP
subsystem for Internet dialup.

<p>
Assuming <tt>/etc/isp.conf</tt> was setup correctly before boot, you only 
need one command to start up the Internet connection:

<p>
<pre>     
  ppp-up
</pre>

<p>
If you use ISDN with autodialing enabled (<tt>ISDN_MODE=auto</tt>
set in <tt>/etc/isp.conf</tt>), you do not need to run <tt>ppp-up</tt>. Just
run a program that sends packets to an Internet host.

<p>
<tt>ppp-up</tt> triggers the PPP daemon, which will dial the provider and try
to login. <tt>ppp-up</tt> can be run by any user in the <tt>ppp</tt> group. In the
default ttylinux configuration, the <tt>ppp</tt> group has no members, so only
<tt>root</tt> can start and stop the internet connection. You can watch
<tt>/var/log/messages</tt> (using <tt>tail</tt> <tt>-f</tt>) to see when the
connection is up and running. After that, the Internet connection is ready
for use. For example, the SSH server will be reachable from the outside
world.

<p>
You can browse the web by using the <tt>retawq</tt> web browser. Use the
<tt>g</tt> key to enter a URL, then navigate around using the cursor and
return keys. You can leave the browser by pressing <tt>Shift-Q</tt>.

<p>
If you use ISDN, you can enable and disable channel bundling by
calling the <tt>bundle</tt> and <tt>unbundle</tt> scripts while the connection
is up. The default for new connections is to always use a single channel,
even if channel bundling was enabled before. To check whether channel
bundling is currently enabled, use the command:

<p>
<pre> 
  service isdn status
</pre>

<p>
If you decide that you want to cut the Internet link, just issue:

<p>
<pre>
  ppp-down
</pre>

<p>
This will take the connection down. Once again, this can be done by
<tt>root</tt> or a user from the <tt>ppp</tt> group, in this case only the
user who started the connection.

<p>
If you change any of the settings in <tt>/etc/isp.conf</tt>, you need to
update the PPP configuration files by running the following
command:

<p>
<pre>
  ppprestart
</pre>

<p>
Note that if you want to switch from using a modem to using ISDN
or vice versa, you need to take down the Internet connection before
running <tt>ppprestart</tt>.

<p>
After that, you can again use <tt>ppp-up</tt> and <tt>ppp-down</tt>. Note
that running <tt>ppprestart</tt> only works for <tt>root</tt>, not ordinary
users. In previous ttylinux versions (2.5 and older), rebooting also
updated the PPP configuration files. This is no longer the case to
allow manual modifications of the files. They will only be created on
boot if they don't exist.

<p>
Users in the <tt>ppp</tt> group will be able to read the file
<tt>/etc/isp.conf</tt> which contains your dialup password. This may or may
not be a good idea, depending on how much you trust your users. If
you only wish to use ISDN, you can remove the group read  permission
with

<p>
<pre> 
  chmod g-r /etc/isp.conf
</pre>

<p>

<h2><a name="SECTION00044000000000000000">
<span class="arabic">3</span>.<span class="arabic">4</span> Using the dropbear SSH package</a>
</h2>

<p>
SSH, or secure shell, is a protocol that allows remote logins
to a machine. It uses encrypted connections and can use public
key authentication instead of plain passwords. The advantage
over the older telnet protocol is that nothing in an SSH
session goes over the network unencrypted.

<p>
<tt>dropbear</tt> is a small SSH v2 server and client package. The
server will be started on system bootup by default. It allows
password and public key authentication. Public key authentication
can use DSS and RSA keys and works with keys generated by the
popular OpenSSH package. Putting your public key from OpenSSH
into the file <tt>.ssh/authorized_keys</tt> should be enough to let
you login from the machine where you keep the corresponding
private key. Please note that the permissions on the
<tt>.ssh</tt> directory must not include group or other write
permission, otherwise <tt>dropbear</tt> will refuse public key
authentication.

<p>
The SSH client program is called <tt>dbclient</tt>. It is different
from the server in that it cannot use keys in OpenSSH format.
You can use the <tt>dropbearconvert</tt> program to convert an
OpenSSH format key for use by <tt>dbclient</tt> or you can use
<tt>dropbearkey</tt> to create a new key.

<p>